Scott Hanselman gives a great overview of Continuous integration tools on this week's HanselMinutes, along with some guidelines on how to make them work together and build yourself a mighty powerful build machine. And if you're not interested in automated builds, at least what you should do is look into TestDriven.NET/NUnit/NCover tripack to help you test your code. TestDriven.NET was recently released with NCover support, giving you even more testing power.
On a side note, in case you missed it :D : IE7 Beta 2 Preview has been released. After working with the first beta, I don't think I'm installing this one. Sure looks cool though.