I used Paint.net for a few years, It just isn't as powerful as I need. I can actually use Photoshop now because the school kindly supplied me with a copy.
I got to use photoshop in my computer graphics class for a semester, and I honestly prefer paint.net over it. I can almost everything photoshop can in paint.net, and some things better. And paint.net is very user friendly, not so ocnfusing.
I dont know if it was just the ****ty Mac computers processing power, but whenever i used any effects in photoshop, a bar came up for rending time and it took like 10 seconds on minimum. Paint.net just does stuff instantly.
Photoshop is superior for any graphical/web related kind of work, I use it all the time and I must say that I can do things I couldn't have dreamed of doing with paint.net.
I mean, if I went over to America and the host saw me on BlackIce, then laughed and said they were one of you, I would probably b surprised to say the least.