hey John,
sounds like you have travelled the world quite a bit already. have you heard about the "Too Tyred Tour"? It's about three US guys going on a RTW-Trip taking 8 (?) years. It's a DVD and probably the only movie about an RTW-tour. Currently I'm planning about going down to Spain and from there on to Fireland to start the journey northwards... Would actually love to go to all places at the same time, but need to start somewhere...
Africa is probably the most demanding and Central Asia is 2nd, so I think it 'd be a good idea to start off going to Latinamerica as german citizens also do not require visas and the language will remain the same from fireland up to mexico (except brazil). BTW: if carrying on to the US: do you think it is possible at all/easy/difficult to get casual work to stock up on funds in the US?
cheers,
Andreas