105 2.5 is great.
28 3.5 actually produces pretty great results, but it is a little tough to focus quickly/accurately and not great for low light because it is so slow. Can focus pretty close though, and if you're using it in daylight conditions you can just stop down and use hyperfocal focusing.
28 2.0 is a great lens but can be a little pricey - wish I owned one.
24 2.8 is definitely worth considering - wish I owned one of those too!