That matrix stuff really isn't as bad as I thought. It's actually quite fun to figure out some compact notations etc. Ill definitely spend some time exapand the generic multiplication formulas for translation, rotation and scaling matrices and have some less naive versions. I also found a nice site explaining the opengl matrices in a pratical way, so I can use the same calculations if I want to. I won't use my own 3D matrix operations for my engine since OpenGL will definitely provide more optimized ones. However, for 2D these are essentially and I'm once again quite excited when thinking about the new possibilities I'll have in the future! Adding projection matrices makes it possible to have my own 3D softwarer renderer in the future! Sure, this will a project for it's own, but I know that I'll need it to fully feel at home when using 3D. I mean just think about the cool stuff you can write when fully specifying everything on your own. I could even try to get it running on the Lego NXT with some very limited lofi software rendering.
Oh boy, I can't tell how this makes me feel better just by thinking about it. I know it's rather trivial stuff and completely unrelated to any typical programmer approach (you know, reading and using), but it's just the way how I work and how I can feel comftable with new stuff. That's probably also the reason why I dislike using random libraries that do the stuff I actually want to do myself: I simply haven't yet done it myself! Strange.