I think it is a very personal decision... For me, I am getting my ADN.. I am 25, ready to start a family, so the Associates sounds good for me... And the hospitals near me will pay for you to work on your BSN while you are working for them... So if I get tired of being a floor nurse and want the more management type positions then I will go for the BSN.. But if I am happy with my associates then I will probably not get it.. So If you are single, no kids, or married no kids... and you know that you want the BSN then I say go for it now... Plus the cost between the two is a major deciding factor for me also..
I would say...if you have time to get your BSN degree, do it while you still can and go all the way. I don't know if that's answers your question, but I'm in the same boat. I'm taking my prereq's now, but to the people that I have talked to many older nurses tend to get their Assoc. degree in nursing b/c it is shorter, they have a family to take care of, and also hold a full-time job...but, as for me i'm pretty young to really give a real definite answer.
I recommend a BSN in the long run...just in case you want to go up...
Like has been said before~ it's a personal decision. For me, we couldn't afford to go that long without me working, so we (husband and myself) decided to go for LPN first (13 more weeks till graduation!), then work 10 months till the RN ASN program starts, and go back again for a year to get my ASN. Sometime in the future, I'll get my BSN, but am focusing on the "close-at-hand" for now!