But, like someone said above...whatever gets the job done. I don't believe in locking myself into one particular solution, so I try to always leave myself a migration path, if needed, to bigger stuff.
But, for a lot of jobs, Linux on a PC works good enough.
SunOS is pretty buggy, but Sun is ok with the patches. The small servers are power pigs too, compared to x86 solutions running linux. They have good hardware reliability, and die predictably. They have great, but pricy (if out of warranty), service for broke stuff. The Sun warranty system is better at keeping records than most admins. Read them the S/N, and they will tell you the day your PO hit, and whether warranty still covers it. Sun is ok, but the best I ever got out of a server was 565 days uptime. Course, we had to unplug the server to move it. GRIN!
/john
Just an anecdote. As I was writing a long note mentioning some computing history, I went to a website that locked up Explorer Windows 98. Yay!
Linux is good because not just because of its price, but that it can do thing that until recently were done on relatively expensive hardware/software. It's good in a company environment because you can recycle older machines to do some non-critical work, saving your money for that expensive, proprietary system. There's a bunch of things it's good for.
Make that older P-II handle you print jobs, and save some money. Or if you want, you can buy a $500,000 50 node parallel computer made of linux nodes.