I read an article about that some time ago... but quite honestly, as I don't use WLM, I don't really give a ****.
And it's not that Aero is disabled. It's just not enabled by default. You can hack that out if you want.
The only gripe I have about my Server 2008 install (got it for cheap 'cuz I was a student) was that it gives page fault errors a LOT, even for compatible softwares. And the source of the error was always illegal memory operations.
Anyway, that means... no No-CD cracks for a number of games, please bear with scratching your discs, no special hack or mod because it might crash the system, mmm... PCSX2 might crash quite often, too, and a lot of Dolphin SVNs don't even give so much as an error. But for what it's worth, the thing is fast. Extremely fast, and extremely stable. Plus if you're programming, it helps nudging you about illegal memory operations.
Edit: okay, found that bit about WLM:
http://windowsitpro.com/article/art...indows-server-2008-and-64-bit-windows-xp.html
Apparently, it doesn't work for 64-bit XP either, so it's not so much a problem with 64-bit Server 2008.