Generally speaking, yes. (there are cut down versions)
But to be honest when each node is running 200gig of ram it's not really an issue

and like I said, buy one copy of 2008 R2 Enterprise and you are good for unlimited guests running 2008 R2

One thing that did bug me about it was they did not have dynamic memory allocation. This was sorted with SP1 though.
Personally, I love Hyper-v. Everything runs rock solid and since the migration to virtualisation our servers have a 100% uptime with no unscheduled downtime.
TBH, this thread is FULL of dodgy info.
This is my biggest concern though, maybe stick to the linux next time KDF eh
Windows Enterprise does NOT give you unlimited vm's, it gives you 4 instances, you need datacenter (licensed per processor) to get unlimited, tut tut!!!
and the comment above about the free version of ESXi giving you the full product without support, again, thats rubbish, it gives you the very basic product without any of the advanced features people like vmware for, its purely for testing or DR sites with no functionality required.
This is my bread and butter, so i can answer any specific questions, but if you want to set up something for free at home (legally) then you only really have VMware server, which is the free product which sits on top of windows.
As for the whole vmware vs. hyper-v debate, thats a whole different thread, hyper-v is not as good as vmware and doesn't carry the same feature set, vmware is the only real option currently for big enterprises to standardise on, hyper-v is going to start to catch up in the the next release, but you really can't go wrong selecting vmware.
Plus, people think hyper-v is free, not if you want to manage it properly its not.............