MobileMonger is a great port of the original SpaceMonger for PC. It gives you a graphical representation of all your data, and you can INSTANTLY recognize the space hogs. I found Opera's cache in 2 seconds that way.
Basically, it shows your device as a square (or rectangle). Inside this square are your files - the bigger the file, the bigger the square / rectangle. I LOVE this beauty! Runs great on my XV6700 w/ Helmi's 6.1 ROM, so it should run just fine on the Omnia.
http://feeds.feedburner.com/~r/pocke...8588/index.php