Apps that I would categorise as 'utilities' are as follows:
theVault (free) - very useful
PlainText (free)
Ping (free)
Dropbox (free) - essential
Calculator (free), but don't like the adverts, powerOneSL might be better but haven't tried it yet.
Perhaps, as another poster has suggested you make a bit more of your website by having a top 10 for several different categories, and also by distinguishing the free from the paid-for.
Just to get you started on some free apps in the 'photo/illustration' category:
SketchBookX (free)
DoodleBuddy (free)
PS Express (free)
Adobe Ideas (free)
and in the 'Apps that will blow you away' category:
BBC News (free) - obviously UK - yea I know it's just a news site but it is so well implemented that it deserves a mention.
Saved the best until last -
MorphWiz 6.99 UKpounds - a simply unbelievable creative music app