Hey webdesigner, I remember you! You were moving to Philly right? How'd that go?
You do earn on all renewals and not just the domains and web hosting but any product that has a renewal fee.
Yes, you can choose to not offer certain products. Login to the reseller control center and under "Products and Pricing" select "Product Offerings". From there you can uncheck any products you don't want to offer.
BUT I will warn you that WWD does a ton of upselling during checkout so even if you haven't selected certain products for your store, they may still be offered to your customers. (Not sure I like that feature and I hope they are working to correct that.)
For example, I don't want to offer the Traffic Facts product because I am all for do-it-yourself self search engine optimization and not buying some submission product. So I chose not to offer that yet it is still promoted during checkout. Although I must say the product has gotten so much better than when they first launched. They do encourage customers to submit themselves and work on building content. I must've complained enough.