Here we get into a real rat's-nest of software. Basically, Linux can run many types of binaries with varying degrees of success: Linux/x86, Linux/Alpha, Linux/Sparc, Linux/foo, iBCS, Win16/Win32s (with dosemu and, someday, with Wine), Mac/68k (with Executor), and Java. I'll just discuss native Linux and common Unix software.
For Linux itself, choices are mostly limited to those available for Unix in general:
Most markup languages are more suitable for large or repetitive projects, where you want the computer to control the layout of the text to make things uniform.
nroffThis was one of the first Unix markup
languages. Man pages are the most common examples of things formatted
in *roff macros; many people swear by them, but nroff has, to me at
least, a more arcane syntax than needed, and probably makes a poor
choice for new works. It is worth knowing, though, that you can
typeset a man page directly into postscript with groff. Most man
commands will do this for you with man -t foo | lpr.
TeX, and the macro package LaTeX, are one of the most widely
used markup languages on Unix. Technical works are frequently written
in LaTeX because it greatly simplifies the layout issues and is
still one of the few text processing systems to support
mathematics both completely and well. TeX's output format is
dvi, and is converted to PostScript or Hewlett Packard's PCL with
dvips or dvilj. If you wish to install TeX or LaTeX,
install the whole teTeX group of packages; it contains everything.
Recent TeX installations include pdfTeX and pdfLaTeX, which produce
Adobe PDF files directly. Commands are available do create
hyperlinks and navigation features in the PDF file.
There is at least one free sgml parser available for Unix and Linux; it forms the basis of Linuxdoc-SGML's homegrown document system. It can support other DTD's, as well, most notable DocBook
Someone suggested that for simple projects, it may suffice to write it in HTML and print it out using Netscape. I disagree, but YMMV.
There is no longer any shortage of WYSIWYG word processing software. Several complete office suites are available, including one that's free for personal use (StarOffice).
Sun Microsystems is distributing StarOffice on the net free for Linux. This full-blown office suite has all the features you'd expect, and you can't beat the price. There's a mini-HOWTO out there which describes how to obtain and install it. It generates PostScript or PCL, so should work with most any printer that works otherwise on Linux. Apparently it's an Office clone and is rather bloated; these are probably two equivalent facts!
Corel distributes a basic version of Word Perfect 8 free for Linux, and has suggested that they will distribute Corel Draw and Quattro Pro as well, once they are ported. This is probably the best option if you have an ARM machine; Corel makes the ARM-based Netwinder Linux computers and is almost certian to offer ARM Linux versions of everything. You can also buy the full-blown version and support, together or separately. The Linux WordPerfect Fonts and Printers page has information about configuring WordPerfect for use with either Ghostscript or its built-in printer drivers (which are apparently identical the DOS WordPerfect drivers, if your printer's driver isn't included in the WP8 distribution).
Applix is a cross-platform (ie, various Unices, Windows, and others) office suite sold by the Applix company. Red Hat and SuSE sold it themselves when it was the only game in town; now sales have reverted to Applix.
AbiWord is one of several GPL WYSIWYG word processor projects; this one has produced a very nice word processor based on an XML format and capable of Word file import.
LyX is a front-end to LaTeX which looks very promising. See the LyX Homepage for more information. There is a KDE-styled version of LyX, called Klyx; the author of LyX and the instigator of KDE are the same person.
Maxwell is a simple MS RTF-format based word processor which started as a commercial product but is now distributed under the GPL.
AUIS includes ez, a
WYSIWYG-style editor with most basic word processor features, HTML
capabilities, and full MIME email and newsgroup support.
Unfortunately, AUIS is no longer maintained.
The KDE project is working toward a whole office suite. I don't think it's ready for prime time yet. The word processor will apparently be a descendant of LyX.
The GNOME project also is working toward various GNU-licensed officey tools. None are available yet, though.
Other vendors should feel free to drop me a line with your offerings.
There are many details to getting decent photo output from common printers.
Ghostscript has some difficulties rendering color photographs through most drivers. The problems are several:
That said, the obvious solution is to use non-Ghostscript software for printing photos, and indeed, such things do exist. The main contender is the print plugin in the Gimp, which supports pixel-for-pixel printing on Epson Styluses and Postscript printers (with basic PPD support). That driver will shortly be available for Ghostcript, as well. Also possible to use for this purpose are the assorted external pnm-to-foo programs used to print on printers like the cheap Lexmarks; these print pixmaps pixel-for-pixel. A print-via-filter option shouldn't be too hard to add to the Gimp.
The best solution, of course, is to buy a Postscript printer; such printers can usually be completely controlled from available free software, and will print to the full capability of the printer.
Color inkjets are extremely dependant on the paper for good output. The expensive glossy coated inkjet papers will allow you to produce near-photographic output, while plain uncoated paper will often produce muddy colors and fuzzy details. Nonglossy coated inkjet papers will produce results in between, and are probably best for final prints of text, as well. Stiffer glossy coated "photo" papers will produce similar output to lighter-weight glossy papers, but will feel like a regular photo.
For photo output on most color inkjets, you should use the most highly interlaced (and slowest) print mode; otherwise solid regions may have banding or weak colors. Generally with Ghostscript this is what will happen when you pick the highest resolution. With Postscript printers, you may need to add a snippet to the prologue based on the settings available in the PPD file. The Gimp's PPD support doesn't include the print quality setting, but I added it in an ugly way for my own use; contact me if you'd like that. If you use PDQ, you can easily add all the printer settings you need in the driver declaration file; for PJL printers this is particularly easy, and for Postscript printers my ppdtopdq utility can help.
Color inkjet printouts usually fade after a few years, especially if exposed to lots of light and air; this is a function of the ink. Printers with ink-only consumables like the Epsons and Canons can buy archival inks, which are less prone to this problem.
There's a program called xwtools which supports photo printing with all the bells and whistles on an assortment of Epson, HP, and Canon pritners. Unfortunately, it was written under NDA, so comes without source. Unless you use it for the Epson Stylus Color 300 on Linux x86, it costs 15 euros for personal use; commercial pricing is unknown.
The ESP Print Pro package from Easy Software supports many printers which might otherwise be unsupported. Unfortunately, since it is based on Ghostscript 4.03, I don't expect wonderful results with this software for photos. But someone should try.