I have 5 GMail accounts up for grabs at the moment. First come, first serve! Just send me an email and I'll send you an Invite.
By the way, my GMail account is roy.dictus@gmail.com.
These accounts are really popular. Google is indeed doing a good job marketing them with this invitation system. But 1 GB of online storage is nothing to sneeze at, and the UI is actually quite responsive. Not as pretty as Hotmail, certainly, but handy. One feature I'd like, though, is the ability to get a clean view of your Inbox (so with only unlabeled messages).
When I have new invites to send around, you'll find them here... :-)