If you are under a budget, you can't go wrong with the Hobbywing Xerun 120A v2.1 for ESC. Plus you don't need a computer around to do the programming. Just buy the programmable card and you can do it anywhere you want.
Power wise, it's just as powerful as the Tekin RS. I have both. Only downside is that the footprint is bigger than the Tekin.
For motor, you really need to know what class you are going to be running. May be go to your local track and ask around. However, if you are really not sure, go with a 17.5 turn. I would say almost all tracks in North America run at least one 17.5 class.
Any named brand motor will work fine. LRP, Tekin, Speed Passion, Trinity, Reedy, etc. I run a Reedy Sonic and Speed Passion MMM v3. Both run great. The Trinity D3.5 17.5 seems to be really popular these days though. May be you can give that a try.