[eogas]

WPF is definitely the way to go. I started a modest sized project a few years ago at an internship, and this past summer I was allowed the task to move it from Forms to WPF. Let me tell you, working with WPF is so much better. Especially when you get into anything custom. Custom drawing in Forms is always a hack, and you basically have to do it in code. WPF is essentially designed to make creating custom controls with custom drawing incredibly easy.

Not to mention all the awesome databinding stuff, and now with async in C# 5, it's easier than ever to create responsive UI. Just reading about the async stuff had me thinking back to that project, saying "yeah, that would make [some chunk of the code] a lot more intelligible".

I contribute a lot in the /r/learnprogramming subreddit, and when new programmers are asking about UI with C#, I generally suggest just skipping Forms. There's really no reason to use it anymore. I can't believe I used it so long while WPF was right there, ready to free me of the Forms peril.

[TheMakeA]

Definitely this. Use WPF if you can. I don't recommend trying to use WPF "as is", but suggest reading about the MVVM pattern and the available frameworks, particularly Caliburn.Micro and ReactiveUI.