You could ally with Iron Hands if you wanted:
Master of the Forge, Servo Harness, Power Sword (you already have Power Fist attacks), 3 Servitors.
10x Tacticals, Meltagun, Missile Launcher, Razorback w/ TL Las
Ven Dreadnought w/ x2 TLAC (elite)
Ven Dreadnought w/ x2 TLAC (heavy)
It gives you even more fire support, and probably still has lots of extra points left.
The other option would be Blood Angels. They're alot of fun. Everything can be mounted on a Jetpack, and there's a few for those points. With 700 points you could easily run two full squads of Assault Marines, a squad of Sanguinary flying Terminators, And a really powerful close combat HQ.