Well, it's too late now. I just placed an order for a Cadian Battleforce, a Heavy Weapons squad and a box of Ratlings. I actually have a fair amount of guardsmen from about 8-9 years ago - Catachans, some Storm Troopers, a few heavy weapons, a Basalisk, a Leman Russ Battle Tank and Demolisher, a Chimera and a few Sentinels. But the truth was, I chose the Catachans back then because they were the most economical choice, not because I actually wanted to field them. Sure, they remind me of Predator. But they won't really cut it for my Gears themed army.
So I'm building out a 1500 point list that uses a fair number of my existing (horribly painted) collection as well as pretty much all of the models I just ordered. Then I'll slowly replace my old IG units with Cadians.
I still need to finalize my pain scheme, although I'm in the process of stripping and repainting my Storm Troopers as kind of the prototype paint scheme for my army. Should be interesting.