Here's the aliens I would want if had an Omnitrix and why:
1. Swampfire: This guy can survive being blown up. Plus If I had Heatblast, I'd be more of a hazard due to my less than average spatial awareness LOL.
2. Chromastone: I'm gonna need something that can handle lasers, raw energy and magic. (Plus I could fly which is a bonus)
3. Big Chill: If I wanna go stealth or just be a difficult target to hit.
4. Blitzwolfer: It's an alien werewolf, that's all I can say (This coming from someone who is known to have an admiration for lycans and lycan-like creatures)
5. Ditto: Probably wouldn't use it to fight but would be a godsend if you have multiple house errands and can multitask.
6. XLR8: Can be untouchable and do some big damage with enough experience.
7. Gravattack: Good for subduing multiple foes by just making them float in the air or just making them collide with each other.
8. Diamondhead: Of course I have to go with the reliable GOAT.
9. Jetray: Gonna need a bird's eye view and travel at high speed in the sky, in the water or in space.
10. Brainstorm: If I wanted to Sherlock Holmes myself out of a sticky situation.
(Pass it along if you wanna share!)