You might also consider installing Quicksilver, LaunchBar, or Butler — all three are quick-launchers which allow you to press something like Ctrl-Space and type an abbreviation of the app name, so entering 'xc' will get you XCode.
It's the same as you're getting with Spotlight, but you can do other useful things that Spotlight doesn't make so easy: if you've entered an abbreviation for a document, for example, you can hit Tab and enter the abbreviation for the app you want to open it with.
Quicksilver and Butler are free; LaunchBar costs money. Butler has the best icon, IMHO :)
Unfortunately I can't give you direct links as my reputation's too low and I'm not allowed more than one — but you can find them all by searching at http://macupdate.com…