I would be all over the Schumacher Mi1 , they recently re-released this chassis as an entry level car. As for parts availability for Schumacher, they don't have a US distributer anymore but I was talking to a guy at the track last week that ordered tires from them direct from the UK and he received them 2 days later in Canada, no shipping
I am assuming they passed the order onto Galaxy Hobbies in Ontario though but still thats a fast deliver.
HPI Sprint2 would be my second choice, parts are easy to get, the car is very durable and the price for an RTR is pretty much unbeatable.
X-Ray's are amazing, parts are expensive and they update their chassis' constantly so a 007 is really a pretty dated car for them.