Used Apple, not a fan. Actually, I like Microsoft, I am just open to other possibilities. Also, I do software development and am looking to freelance again soon and don't want to turn down potential projects just because it's a Linux server and not MS.
I'd suggest spending more time with the new Solaris. It has some advanced server management capability that Linux doesn't offer, plus Sun is the originator of Java technology.
I think we're going to see significant growth of Solaris over the next few years, as it will offer a standardized platform (unfragmented like "Linux") that commercial vendors won't be afraid to develop commercial applications and hardware drivers for. Lots of programmers are rightfully afraid of mixing their wares up too much with GPL code, as they will send their lawyers after you to confiscate your code if you accidently tie any of yours too closely to theirs.
http://www.forbes.com/2003/10/14/cz_dl_1014linksys.html