300Mb harddrive is kind of small... try get hold of something bigger (4Gb is ideal).
Depends what you're using it for. I don't use my A1200 much anymore, but when I did use it, I think I used about 150MB max (850MB disk).
The accelerator also really depends on the use of the machine. I think the main thing holding my A1200 back is the lack of graphics power, not the 040/40/FPU.
I can't play back 128kbit stereo mp3s on my A1200 (can play 56kbit mp3s). Allegedly I could with an 060.
