I did a small search for Guilty Gear threads, but it seems most of them are dead for at least two months. And since the bumping of old topics is against the rules.....
WHAM! Rebirth of the Guilty Gear thread.
I have started playing GGXX #Reload recently, and it has totaly captivated me. The speed, the combo's, the anime, and more importantly, Dizzy!
Indeed, Dizzy is by far my favourite character for figting. Following her is Chipp. A strange combination, since the two have completely different fighting style, but I suspect that is actualy the reason. Sometimes you need a different strategy to defeat you opponent (especialy when you have button bashing geniuses like my sisters).
In terms of characters, however, my favourite list would be Dizzy first, followed closely by May, then Jam and rounding it up with Bridget (and yes, I am fully aware he's a guy).
Edit: On a side note, GGXX2 #Reload is also available on the PS2. That's were I played it.