Anybody using it, how many vm's, and how's performance?

I'm looking at migrating over time to VMware infrastructure. Currently
I have at least one unused server that would be ideal for it. If I go
that route my plan is to have two servers running it in a high
availability mode. The host would include e-mail server, two terminal
servers, and possibly two sql servers (all this over time) as guest.

The SQL Servers are my biggest concern. SQL Server being such a
resource hog.