Jeff Francis - Probably the least known ace in the National League by fans, however he was chosen as one of the top four starters in the National League by the players this past year when he won 17 games and struck out 165 while only walking 63, been compared to a left handed Greg Maddux.
Aaron Cook - Has battled some interesting injuries including one that almost took his life while in the mound. However he's possesses one of the best pitches in the Majors, a sinker that rivals Brandon Webb's and is a solid inning's eater who has suffered from a lack on run support.
Ubaldo Jimenez - A young pitcher who was called up last year, who has nasty stuff, 96 mph fastball with a better slider, and profiles as a future ace
Jason Hirsh - Another rookie last year, whose season ended when he got hit in the leg with a line-drive in the first inning of a game, he proceeded to throw 6 scoreless innings before being pulled and discovering he had a broken leg. Was the #1 prospect in the Astro's system before being traded to the Rockies as part of the package for Jason Jennings.
Franklin Morales - A very young left-handed pitching with an amazing curve, and a 95+ fastball, he had a 3.43 ERA over a forty inning call-up last year. Considered the top prospect in a very good minor league system
Also of note the Rockies pitching staff had the best ERA in the National League and was top 3 in the majors after the All-Star break with these guys. It wasn't the Rockies hitting that got them to the World Series it was their pitching. They shut down the vaunted Phillies' offense in their little league field.