I got photoshop 7 a couple years ago for just $200. It's got everything a pixel artist needs plus the full suite of other adobe tools, and its a legit commercial license! Ah, the wonders of used/outdated software and ebay.
While I do use promotion for 90% of my pixel art now, until it has layers i do need photoshop for some things still, and the CS series adds very few pixel-useful features at the cost of a lot lower performance and a much higher pricetag. No thanks!
Photoshop makes a good glue app too.
I've tried GIMP before but the interface is too frustrating and slow for me.
So, to sum up, if you have $300 to spend on art software, full commercial licenses of Photoshop 7 and Pro Motion will get you farther than an academic license of CS3
