UNIX (and UNIX-like) OS's for the x86

Since I love UNIX and only own PC's, I've compiled this list. It's certainly not definitive and my descriptions are far from authorative. Please mail me at gmd@yellowleaf.org with comments or any additions I could make.

UNIX's for 680x0 Macintoshes and Power PC's, YeeeHaw!
Links to some great operating system info pages.

(limited license, UNIX'ish)
A distributed OS, needs multiple machines to run
BSDI* I've worked for two ISP's that ran this, at least one of them is still using BSDI (the other switched to RH linux). (X11)
Coherent The manufacturer is out of business now, may be able to pick up a used copy from comp.os.coherent. 80286 and up. (compatible with V7, no X11 support)
ELKS The Embeddable Linux Kernel Subset. Requires as little as 120K RAM, on an 8088 and up. Networking, swapping and other important things are still under development (as of 5/23/98).
ESIX* Used to run this as news server on a 486DX66, crashed a lot, but then the disk filled up a lot and the traffic was high. (Pure SVR4, X11)
FreeBSD* (free) A great choice, the support for this is good (as in USENET and mailing lists). x86 only (as of 2/98), Alpha port in the works. (from 386BSD 0.1, X11R6)
GNU Hurd (free) Gnu's OS. Still very beta at the moment (the moment is 9/97). (Mach3 kernel, no X so far)
Interactive UNIX "The INTERACTIVE UNIX System is targeted primarily to small- to medium-size organizations as a low-cost, resource-sharing, multiuser system." -- Sun. (SVR3.2, X11)
Linux* (free) Probably the most well-known of the free UNIX's. Everybody and their kid sister runs it. (POSIX compliant, X11R6)
LynxOS A real-time UNIX-like system (runs on half a dozen architectures). (POSIX compliant, X11R5)
Microport (Pure SVR4, X11)
Mach 4
4.4 BSD Lite Server
The Mach microkernel from Carnegie Mellon, runs on some of the *BSD's, Linux, and the GNU HURD.
(free, limited license)
Great for that 8088 with 640K RAM in your closet. Runs on Intel, Macintosh, Amiga, Atari, SPARC. Easy install. (V7, no X11 support)
(free, limited license)
Minix + virtual memory & X-Windows. (V7, X11, working on POSIX compliance)
NetBSD (free) Supports many many different architectures. (from 386BSD, X11R6)
NEXTSTEP The ever-hip NeXT has been bought by Apple but hopefully will live on, runs on SPARC, x86, PA-RISC, mk68k. (X11R5, BSD on Mach kernel)
OpenBSD* (free) Runs on over a dozen hardware platforms. Very security conscious. My choice of the *BSD's, but not as user-friendly as FreeBSD. (originated from NetBSD, X11R6)
Plan 9
(UNIX'ish, free trial)
From AT&T, sounds neat.
Realtime UNIX-like OS based on a microkernel architecture.
($19, limited license)
$19 for UnixWare (SVR4.2) or OpenServer (X11) CD, complete system. (X11R5)
Free for non-commercial use! 386 and up. (SVR5, X11R6)
386BSD (free) The mother of the *BSD's, no longer supported. (from Berkeley Net/2 release)
(sharware trial)
An odd sounding UNIX system. A 2-user shareware version without networking support available to download.
Xenix The oldest Intel-based UNIX, from Microsoft. Dead ages ago. (SVR2)
Xinu What is this?
*Means I've used this OS, so the description may be a little less BS than the non-starred ones.

In my "check this out" list:

http://world.std.com/~mikep/rtx-page.html  RTX (Real-Time Operating System)
Eurix (80?86) SVR3.2 (Germany) 
Generics UNIX (80386) SVR4.03 (Germany) 
PC-IX (IBM 8086)SV 
UHC (80x86) pure SVR4, X11, Motif