I have a 2008 Cobalt and want to put a remote start on it. Are there any suggestions for the best that would work with my current system? Also, is it worth it to get the fob with the remote start button on it? I need to purchase another fob anyway because I was only given one when I bought the car.

 

I really wouldn't suggest you do this install yourself if you were thinking about it. I would also get someone who has done a few cobalts before as well.
they are a bit complicated for a average tech.
As far as which remote starter to buy, get something you like. Aside from the real cheap ones(walmart brand) they are all pretty good and there are really only 2 or 3 manufacturers making the modules under a bunch of different names.
You will needa by-pass module to get around the factory security and the transponder chip in the key. I highly recommend a module from idatalink. specifically an ADS-AL-CA with the GM2 software on it. These modules work great, and not only will they bypass the security in the ignition, they also control the door lock via data