Ooooh, the Jesus Debate has resurrected! I do love a good resurrection 
My take on the Dionysus thing is a bit different to Mad's (with all due resoect to Mad!). I think that there are definite parallels between Jesus and Dionysus, and, going back to my hobby horse, that it is historiclly plausible that the Gospel writers, John in particular, could well have known the Dionysus myths and therefore 'used' them, esp. in the water to wine story. However, for me, the issue is this: John is a storyteller, a writre who writes 'in order that you may believe and have life'. As such, I am interested in how John may use the Dionysus motifs, and what kind of conclusions to leads onto from them. I have no problem with the idea that John uses aspects of the Dionysus myths to make points about who Jesus is - and the thing that John does, over and over again, is to imply heavily that Jesus is God incarnate, and that in Jesus, God has saved 'the best until last' (like the wine).
For John, it's not just (just!) that Jesus was resurrected - it's that Jesus is the resurrection. It's just not that Jesus can multiply bread in the feeding of the 5000, it is that he is the bread of life. Every 'sign' (or miracle) that Jesus does in John's Gospel is selected by John, as a storyteller, to tell his readers something about who Jesus is, so that they might believe in him. So I can see that John may well be making the point that Jesus is greater than Dionysus, but that point is rooted in John's central claim about Jesus - that he is the 'great I am', Yahweh (which means 'I am') made flesh - so all the 'I am' statements in John's gospel are ways of saying 'Jesus is God, and this is what God is like' (i.e. shepherd, resurrection and life, bread of life, way, truth and life, etc). So for me, allusions to Dionysus don't cause me any anxiety because I can see how John may have evoked Dionysus to say that Jesus is greater than Dionysus, and also to make the point that in Jesus, God has saved the 'best until last' (the conclusion of the wedding at Cana story).
Anyway, in many biographies, real peole are comapred to literary figures - why can that literary feature not be present in the Gospels?