I've got a website that basically does the same thing as many pieces of desktop software do.

Adsense on my site advertises these. I dont want to go in and block them all. I feel like adsense is "getting" what my site is about, but it isnt quite doing a good job of showing relevant ads.

My site is tool that resizes images. I'd like to show people ads for things like digital cameras, cellphones with cameras, etc. -- not ads for software packages that do the same thing as me.

Is there a way to "fix" this ouside of keyword stuffing the page?

I'm not sure, but you may find higher returns from affiliate offerings rather than PPC ads. Perhaps even CPA offers.. although it depends on your current users.