Hi there, I thought I'll reply quick 'cause I couldn't find this info anywhere on the net when I got my laptop with Windows 7 Home Basic 64bit.
Any Windows 7 is fine for doing .NET dev. You will obviously be installing Microsoft Visual Studio 2005/2008 or 2010, right? If you're going to be doing Windows Form / Windows Program development, then there's no issue at all, you'll be fine. If you're going to be doing web development, ie ASP.NET / ASPX pages, then you'll also be fine, 'cause Visual Studio will install the Web Development Server (Casini) - so you'll be able to run and test your apps perfectly.
The only irritating thing about these entry level Windows 7 package (Home Basic / Home and Start) is that they don't come with IIS at all, and you also can't install IIS. I read before I bought my laptop that you can actually install IIS though some amazing hack onto these versions of Windows, but trust me, it's IMPOSSIBLE. Your version of Win 7 either ships with it, or you don't have it.
So what irritated me was just that I didn't have IIS - I like to be in control of the entire development process and there are sometimes some things that you want to tweak in IIS to test before you go live on your server, but it's definitely not a neccesity. All my developers at my company are forced to use the built in development server 'cause I'm too stingy to buy them Win 7 Prof or Ultimate!
So to summarise, any Win 7 is fine for .NET dev, but if you're going to be doing crazy ASPX dev then it would be nice to get a version of Windows 7 that ships with IIS 7 or 7.5.
Another tip, if you're going to be using Visual Studio 2010, you'll find that no matter what spec your PC has, dual, tripple, quadriple core, it's very slow. Replacing your laptop hard drive with an SSD (solid state drive) and installing Win7 and Visual Studio on it will make it fly - a 64BG SSD is about R800 now and it's the best investment you can ever make for a laptop!
Oh, and I forgot to mention - you will see that they always make these nice little claims that you can easily upgrade your Win 7 start or Home Basic to a bigger version of Windows, but when you try to do the upgrade wizard thingy, it will tell you that you can't do it in South Africa (and no matter what you make your regional settings, it won't let you upgrade). Only way is to go and buy a physical CD and upgrade.