There are so many models I would say just get something that you like the looks of and are willing to spend.
Some good reference sites are Casio's site and a couple of blogs.
http://www.casio.com/products/Timepiece/
http://mygshock.com/
http://50-gs.blogspot.com/
Some good reference sites are Casio's site and a couple of blogs.
http://www.casio.com/products/Timepiece/
http://mygshock.com/
http://50-gs.blogspot.com/