Custom keyboard shortcuts to change active Spaces desktop
The built in methods for changing shortcuts are less limited than you think.

Go to the Exposé &amp; Spaces preference pane in System Preferences, and check out the bottom section of the preference pane. Note especially the text just above it:


  Keyboard and Mouse Shortcuts (for additional choices press Shift, Control, Option, or Command)


Here's me pressing ⌃⇧⌘ (Control + Shift + Command) while the shortcut drop-down is active:


The shortcuts have the keys I'm pressing added to them (well, sort of, it avoids redundant combinations but its very easy to see how it works and choose exactly what you want).

So for ctrl+alt+arrow keys, open the drop-down, press ⌃⌥ (Control + Option) and you'll note the top item becomes the shortcut you're after.

You can also do the same for the shortcuts to switch directly to numbered spaces or for the Spaces activation shortcut.