Best Lightweight Photoshop Alternative?

I'm not artistic enough to understand what new versions of Photoshop bring. Me and Photoshop CS5 are going to be together for a looong time.
 


Photoshop CS5
RAM
SSD

= Flawless.

I spend 4 hours/day in Photoshop, sometimes 6-8. And I'm on an HP DM3 laptop, which is basically an older dual core with 2GB or so of Ram. Photoshop loads in 10 seconds, and I can have 20-30 tabs open at once. Leave it running for days and have zero issues..

In short. You don't need a lightweight alternative, stop bogging down your machine with other shit..

:)

ps. The best setup is to create a guest user in Windows. Only use that guest account for Photoshop editing. And set that to pretty much only run Photoshop with no background processes.
 
I went for the Photoshop 7 / Paint.Net combination. Working well on my minilaptop, thanks for the suggestions