It really all depends on how creative you want to get. As I understand it, the sensors on the DSLRs are physically bigger, giving you more picture for the same number of pixels. (I really don't understand it, but everyone tells me bigger is really better.)

I have a canon EOS 1Ds Mark 11 (the one with the full size sensor). It is heavy and the lenses are heavy. It is a bear to drag around. I take it when I travel because I love to take good travel pictures.

I also have a canon G4. Both take great pictures. I can get much closer with the dslr and my 400 lens. The pictures are sharper; I can crop till the cows come home and still have a great 13 x 19.

I use filters with the dslr. There are filters for the G4 and add on lenses; I just haven't gotten them.

It is much easier to play with apertures and filters with the dslr.

I hate tripods, but they are almost essential with the Mark II.

It really depends on how much photography becomes a hobby for you.