If you have never flown going with a Blade msr or mcx2 ready to fly would be a great start. If you have some experience then something like the 120sr or going into a blade nano or stock 130x.
One thing with the 130x is you may need to make two or thee upgrades. If your just working on orientation and forward flight those upgrades may not make a difference.
If you have experience and want to make that jump to something bigger then either a 450 class or 500 class. I would lean more towards a 500 class if you can afford it, if not then a 450 will be just as good.