I am planning a trip from sydney to melbourne and back.

I am planning a trip from sydney to melbourne and back. Which airline qantas or virgin or for low cost airline jetstar or tigerair

Wow

Qantas and Virgin Australia now have a fairly similar ground and inflight experience. Choose whichever airline, if any, you have status with. Both of these are far preferable to Jetstar, and Tiger Airways should probably be avoided.

Well it's only 1h 20m to handle so I guess Jetstar is fine. But DO NOT go on TigerAir, they gave us headaches in Sydney with gate changes and delays and not putting them on screen. Jetstar is at least better than Tiger. Qantas and Virgin are there if you are looking to spend your stash but if not then Jetstar is the best way to go for a seemingly short flight each way.

Yes and no. Jetstar is often no cheaper than Qantas, and on one particular evening I was looking at, was actually actually more than Qantas, before add-ons like baggage.

OP should fly Qantas.

Fly Qantas. Best experience all-round.

Always fly Qantas where possible

Qantas. Always

Qantas. Terminal 3 is much more civilised when departing Sydney.

SYD - MEL QF is Better. They have more flights 
VA is always good as a second option. Generaly I find the pricing to be similar but VA is cheaper by $10 aprox