As far as a Photoshop replacement which one would be best? Anyone play with either of these?
I’ve played with them both a little, and I very much recommend GIMP if you are looking for a more Photoshop like program. Paint.NET is ok for some things though; download both and see which you like! Paint.NET is a little easier to use (to me) but it does less, which is why it is easier to use, actually. If it will do the job, you may be happier with it, but GIMP is good for more advanced stuff. I would try both as I said. 
I’ve never used Paint.NET, but I’ve messed around a bit with GIMP, and I really like it a lot. It’s much easier (to me) than Photoshop.
Here is a good review of both programs plus a couple more:
http://www.techsupportalert.com/best-free-digital-editor.htm
Hope it helps.
Have you considered picasa? Dopers recommended it to me and I like it, though I don’t manipulate photos beyond basic stuff.
I’m pretty Mac-centric and from the mention of Paint.NET I assume the OP is on Windows. How about Paint Shop Pro? I tend to think of it as the PC equiv of Graphic Converter. Nice little app.
Paint.NET - well, it’s more intuitive in a sense that it uses the same Window mechanics as most other Windows software. For GIMP, it runs like a Mac application and it takes a while to get used to it.
But GIMP is pretty powerful in its own right, with its own scripting language and automation. But for simple editing, I’ll just stick to Paint.NET
Corel ate Paint Shop Pro. The current version (X2?) seems to be completely focused on photo manipulation, while they’ve split off the drawing tools and so forth into a different program, the name of which I can’t remember. Something clever like Draw or Sketch, I think.
I’m still using PSP 8, but I’ll bite the bullet and buy Photoshop once I’ve saved up enough cash.
Unless things have changed recently, the Gimp on the Mac needs the X11 windowing system, which is an optional install from the system disk. You then get a whole collection of Gimp windows, with internal menus, that don’t behave at all like normal Mac ones. Some of them are toolbar windows, and it’s a bit odd because if a different window is selected, you have to click icons in the toolbar twice: once to select the window, and a second time to activate the icon. Then you have to click the image window again to select it…
I agree. I can tell GIMP has some advanced features - I just seem to struggle to find them every time. It’s the multi-window interface that does it, I think (although I seem to cope fairly well with that sort of thing in other cases)
I think Photoshop is going to have a free online-only version, sort of like Picasa in its capabilities.
There’s a hack for The GIMP called “GIMPShop” that changes the way GIMP looks, so that it’s menu layout is the same as Photoshop.
You’ll get better answers if you tell us what you want to do with it. If you’re cleaning up home photos, any of the answers so far will work. If you’re preparing photos for professional CMYK printing, or need to manipulate images in non-corrective ways, you’ve got a lot fewer options (basically none).
I have a feeling that CMYK colour spaces (a significant deficiency in the GIMP that was recently solved) haven’t made it into that version yet
I use GIMP for basic photo manipulation and I love it. My main uses are resizing photos, adjusting color levels, and cloning out occasional dust spots from a dirty sensor. I’ve found it really easy to use for minor tweaks like that.
I never really used Photoshop, and I couldn’t for the life of me figure out how to use GIMP.
Yup, I downloaded GIMP so I could try and play in the Fark PS threads, but apparently my skills are totally non existant. I deleted the thing.
Paint.NET = Leatherman
GIMP = Big cantilever tool-box filled to bursting
Given that they’re both free, no reason not to have both and use each for whichever it’s best at.