Ha ha - yes, it can be if you want everything such as IM, presence, remote access, federation, LiveMeeting, MSN/Yahoo/AOL integration as well as telephony.
If all you want is IM & Presence it's a doddle. You can virtualise it too.
OCS is my bread & butter - you're right full suite is complex, but it's incredibly flexible.
OCS Std Edition is about 400 quid. You then need client access licenses - standards are about 20 quid, enterprise about 120 (at retail - far cheaper for EA/Volume). Also, you need Communicator 2007R2 as well - it either comes as part of Office 2007 Pro Plus or above, or you can buy separately at about 17 quid/seat.
Or license per device.
Personally I think the licensing is more of a ballache then the product itself.
See here for building a standard edition set up, including video run throughs:
http://www.markc.me.uk/MarkC/Blog/Entries/2009/6/19_Building_an_OCS_Test_System.html
You need quicktime to view the vids (sorry!) and the page takes a while to load cos I haven't optimised it very well*.
*At all.