Pretty easy questions, Umphlett!
1. what are the best model kits for someone returning to modeling
Those would be models of whatever you are interested in. I didn't start building models because I like models. I started building models because I like armor and aircraft and ships and automobiles. Plus, the real things are kind of expensive, and in some cases, hard to get.
2. what are some good modeling manuals.
FSM: the magazine and the website. Plenty of great stuff in both, covering all genres of modelling.
When you decide specifically what kind of stuff you want to build, there are plenty of specialty books out there.
Hope that helps!