I have the Sharp Zaurus SL6000-L and really enjoy it. It is larger than most PDA's, but has a beautiful 4 inch very sharp color-saturated 640 x 480 resolution screen. It supports on-the-fly screen rotation from portrait to landscape view, has an integrated slide-down keyboard, a CF slot, SD slot, WIFI, (no Bluetooth) speaker, microphone, audio jack, a user-replaceable battery, IR port, and a USB host port. The processor is a 400 Mhz Intel Xscale, and it has 64 MB of SDRAM, and 64 MB ROM.
It has Linux preloaded and works very nicely for my needs. Software that comes with it includes: the obligatory addressbook, calendar, calculator, and to-do list, as well as e-mail program, Opera web browser, Hancom Office, a media player, (mpeg movies, and mp3's) an image viewer, text editor, world city clock, software add-remove program, and voice recorder.
I use a Pockettop IR keyboard with it when I don't want to use the little integrated keyboard, and a USB mouse. I also have a CF GPS card that works with it, and a CF 56K modem. If you plug in a USB hard drive or thumb drive and set it up correctly, it sees it and lets you use it. Others have reported using external USB CD burners with it, although I have not personally done that.
Other software I have added is Qconsole, (a terminal) Kismet, (a WIFI detector) Tree!Explorer (a file manager), Qpdf (pdf viewer), Kino2 and Mplayer, (supports a greater variety of video formats) a bunch of games, Gaim (a multi-format instant messaging program) CloverPaint, and QpeGps (a somewhat limited GPS program) Textmaker.
Check out: http://www.oesf.org/forums/
EDIT: Also check out pdaxrom, a debian-based rom for the Zaurus:http://www.pdaxrom.org/