I just went through that exercise this summer when prepping for LeMons.
Hans vs DefNDer - I went w/ the DefNder. It was more comfortable, cheaper (when you added in all the Hans options tht comes standard on the DefNDer), provided the same level of protection and is approved for SCCA and NASA racing. It also has a level of side restraint in the tethers that Hans does not.
Suits - I went multi layer. That way its much quicker and easier to get into the suit since you technically don't need full length under garments. Find a local source/dealer so you can try on the suits that fit your budget. Fit is very subjective much like choosing a helmet. The differences in feel and comfort between brands in the same price range is huge IMO.
Gloves - see above where I say to find a local source and try them on. I'd recommend getting a high contrast color for the gloves. makes it easier for drivers and workers to see any thing you might be trying to say with your hands.
Shoes - see above statement on local source. They are difficult to size w/o trying them on.
If you are local to Northern CA, I'd suggest calling the owner of:
http://cs-gear.com/
He is here in the Bay area and is really nice to deal with. I got my Pyrotect suit and Pyrotect shoes from him. I found them to fit better and feel more comfortable than the Lico stuff I tried on at the shop at Infineon race way. The Pyrotect stuff fit my low budget and offered good safety ratings. The slightly more expensive G-Force suit he had was more comfy and nicer looking but another ~$100
So in summary - find a local source and try stuff on.
I find that local race forums (scca) or the local sections of bimmerforums is a great way to connect with local racers and get references to local shops. The local chapter of my SCCA region had links to local safety equipment suppliers and was a great source also.
