I forgot that R14 and below have that stupid dongle. I wouldn't waste my money upgrading because I have issues modeling a radiator in 2008 at work. Of course that's mainly graphics related because I have a lower end workstation, although you would really like some of the newer features. From what I've read 2010 will be an awesome release with 2d and limited 3d constraints and some more advanced modeling commands.
I'm still amazed at what you are doing with that antique release.
I started with r14 and switched to 2000 a few weeks later. I really cut my teeth on 2004 at college and have used 2008 at work for the past 18 months. I specialize in 3d techniques and I would be hard pressed to replicate your efforts, that's assuming I could even do it.
Actually, my copy of R-10 does NOT have the dongle, nor does my copy of R-12.
When I started my Engineering Degree, I had already been a CAD Draftsman for years. I have been specializing in 3d AutoCAD since 1990. My Engineering Fundamentals Prof had about 4 months experience with AutoCAD (prior he had used CadKEY) at a point that I had 4 YEARS'. I did the Term Project as a homework assignment (had it done to hand in the next day). Needless to say he put me on a special assignment for my Term Project. I wound up using AutoCAD r12 to generate a 3d model of something, then plugged that into 3dStudio (note the lack of version number - it was the original) and rendered a 266s multimedia animation sequence, at 320x240. On my 486DX2-66 with 16MB RAM and 540MB HDD it took three weeks to render (That was a cutting edge system in those days).
Don't cut yourself short on what you can do. Given enough time, enough practice, you can be very good at it. The number of hours I have doing AutoCAD is simply enormous - for someone who no longer does it professionally. It will take years for a beginner to get to my number of hours, but you will eventually match and surpass me if you spend the time. If I can provide you a good example of what you can achieve in the future, then I have achieved my goal.