First of all, Mike! Glad to see you have found your way back to the fold. As for the best kits available, for every person who answers you will probably get a different opinion. But, here's mine: as far as overall quality, ease of fit, and general accuracy you really cannot beat Tamiya. As for the cars, they mainly do the more exotic ones, and if your auto interrest lay in muscle cars then Revell/Monogram is just about the only game in town. Hasegawa also makes wonderful aircraft models, and the armor scene has really taken off with the advent of the new technology that Dragon has brought to the table. Sorry to ramble...
Here's a link to Squadron, a wonderful mail order hobby site. Good luck in your modelling!