Now in regards to lock in. How is it different from any other stack? If I build something with ASP.NET MVC (which has the source available under the MS permissive license) I can run it on Windows or any machine running Mono.
Spend a week writing C# in Visual Studio.NET with ReSharper installed, then try to go back to your old language and IDE. You'll understand.
I spend entirely too much time in Eclipse hitting ctrl+space and getting nothing back. Often even when the thing I'm looking for is in the same file, let alone included thru an import. ReSharper will find references for things I haven't even imported. It really is that much better.
Oh, and VS.NET does have open source and commercial plugins (of which ReSharper is a good example.) It's every bit as open as Eclipse as far as extensibility is concerned.
In general, I find it's best when offering comparisons of two products to have actually used both products. That is the basis by which I consider VS.NET to be superior to Eclipse. I'd suggest you try them both before making up your mind for good.
I don't care what you use, it has lock in of some kind. Get over it. VS2008, C#/VB.NET, ASP,NET, MSSQL are great tools. That's all these things are: tools. The end product is always the same. If you build something with Ruby you can't go back and fix it with PHP. Lock in? Yep.
Sure, there's lock in and perhaps Microsoft is engaged in anti-competitive practices. They are a business, after all. But what is wrong with the tools? Visual Studio, C#, VB.NET, IIS? Point out some real issues like the current state of ASP.NET's AJAX toolkit or linq2sql's inability to do perform joins efficiently without an associated view.
I might be playing devil's advocate here, so please don't take me the wrong way. I just want people to look at their tool box more closely and make decisions on real, measurable things.
Disclaimer: I work on everything from ColdFusion, PHP and ASP.NET to Perl, cmd and shell scripts. I have no zealotry in me except for an extreme love of Adobe Flex, Adobe AIR, Macs and the opposite sex.