I'm a little overwhelmed at the amount of e-mail I'm getting about how I like Parallels on my MacBook Pro, which is what I've been using for Visual Studio, SQL Server and Photoshop development. I guess I'm not going into enough detail with my other posts, but that's partly because there's no detail to give.
Keep in mind that the machine is already a 2 GHz Core Duo, so natively for Windows, it's pretty damn fast. I have 2 GB of memory, and I'm giving Parallels a gig. Usually in OS X I also have Adium, Firefox and sometimes iTunes or iPhoto open.
Ihave no performance issues to speak of, which is to say none that wouldn't already be present in Windows. I first ran Windows with Boot Camp (that was the motivation to buy the MacBook Pro at all), so I have a good frame of reference to compare to. Parallels says there is some performance hit, but whatever that is, I'm not seeing it. All of the development tools play nice and work just peachy. So peachy, in fact, that I'm pretty sure I want to buy a Mac Pro now to replace my aging desktop. Perhaps later in the year.