I was faced with the same problem - I have a loan for my car (I have about $3800 left to pay on it), but i wanted the 300D. I have wanted it for a year, and finally got it (when they discontinued them). My mum kindly put the bill on her credit card and I am paying her back. I only have $300 to go, from a $1550 bill.
If you have been thinking about it for a while - get the DSLR, if it is a new thing - wait a while. it makes it more rewarding in the long run, to finally get something that you have wanted for ever. (And once forever arrives - if you still want it, you won't regret it.)
Hmm - I clicked "get DSLR"... If being in debt doesnt worry you - get the DSLR - and you could make money and save money on not using film and having to get it developed. if you dont wanna be in debt - pay off your loan. (Maybe put the extra towards a body - or see if the store will do a layby for you, and you could put money towards getting a lense and body)