I have recently moved a large project form VS 2003 to VS 2005 using the new Web Application Project Add-In from Microsoft (Details at ScottGu's Blog here).  All went well and VS 2005 is for the most part great. 

However there is one big issue I have with VS 2005.  With one specific solution I'm using it is using LOTS of memory, sometimes my virtual memory goes over 1GB, sometimes up to 2GB.

Some details are over at the asp.net forums here.

I was able to reproduce the problem with a very small solution with just a Web Site Project and a Class Library.  The example solution is attached.  You can open and close the default.aspx page and every time you open it the memory goes up, but when you close the file the memory does not go down.

MS is looking into the issue (they have been very helpful) and I'll post any updates as they arise.