Frankly, most web designers could get by happily with Pixelmator.I'm not saying Adobe is amazing, but if you need more than just basic photo editing (especially if you're a web designer or graphic designer), you don't really have a choice. The other options are either still lacking in usability, features, or support.
If you need 16-bit, CMYK, Lab: Photoline is getting a lot of attention.
Corel's suite is also coming back to the fore.
Quark is seeing people returning, who moved away to InDesign.
There ARE professional alternatives out there for the whole range. Maybe they haven't got all the features; maybe they have: but they'll certainly be keen to develop their software if it attracts people away from Creative Cash.