I think using a 4000 with a good graphics card would be a good option for you if you want to do image generation/processing with it. A graphics card will not turn the machine into a PC. It will turn it into a better Amiga: more pride for you. The Picasso IV would probably be a good choice, as it has a great on-board scandoubler/flickerfixer, which will allow you to use all your native video modes in their full glory.
Is your 3000 not functional now? Is that the reason for wanting another machine? As mentioned before, the 3000 really is a very capable machine. I've used a 3000 for paint progs, 3D modelling, writing music, games, word processing, mathematical modelling, spread sheets, etc. All very impressive in the day, and still usable now.
You also mentioned flaming and slagging: unfortunately there is a bit of that around here, but really not much. Generally, the people here are more than enthusiastic to help, and there really is an impressive wealth of knowledge in amongst the forum members here (I'm not talking of myself here).