50cc is a great entry into gas! Very very easy to maintain and live with and lots of performance

Engine:
DA50
BME 50
3W50
DL 55

Plane:
Wild Hare - Any
Great Planes - believe it or not the Cap is a great flying plane and cheap!
Aeroworks
Extreme Flight
Lots of good choices!

Servos:
Hitec 5955's
JR 8611's
Futaba
DS120's or HD 150's (cheap and good)

Battery:
A123 x 1 for plane and no regulator!
any 4.8 nimh or get another A123 and use a regulator to 4.8v depending on your ignition

Fueler:
1-2gallon gas can and $20 pump
or
Jersey Modeler or similar

I am guessing you have a good TX and RX. Honestly 50cc gas is easier then glow IMHO. Shop around and you will find some package deals. A good used 50cc plane can be had for $1k or so.