Grazie, Loggins!, much like you guys i love the series and i think it's easly one the best manga series out there (if not the best). I started the franchise with PART III OVAS in 2006, but have played the PS1 game without really knowing the series back then in 2000, and since them I religiously follow the serie.
I already complete the manga series and I'm reading Jojolion now. But I did it on a "bizarre" way, starting with PART III, them going to PART I, PART V, PART IV, PART II, PART VI and PART VII. Yes, weird indeed.
It's hard to pick a favorite part, but i guess PART III and PART V got me into the serie. Also mention it's hard to pick a favorite character too, but besides the Joestars and Dio, i would choose Guido Mista from PART V.
I hope to contribute on JJBAWikia as long as i can.