I say go for the moderate!
1. BECAUSE you don't have any kids ... it's more quiet (typically) at the moderates and even if you are planning on being out at the parks all the time, it's nice to have the option to go back and relax at a quiet pool or walk around the grounds together and have a romantic moment.
2. If it's only 250 more dollars, to me, that's money well spent. I'm a hotel girl though and I have been to every moderate there is except POFQ (which I'm going to in september) and love them all. While I do think the value resorts are nice as well and have their place, I think the moderates have a nice atmosphere and feeling to them in general. Maybe you can work a little overtime at work to make up the 250 dollar difference if it's really that big of a deal to you.
3. Have you been to WDW before? If so you may want to take some time out from the parks to just relax and enjoy yourself. To me, vacations seem to last much longer if you stop and smell the roses so to speak instead of focusing on getting every ride done commando style!
4. If you're staying longer than 4 days .. then yes, go for the moderate!
in conclusion....
go for the moderate! haha.
ps. I also think CSR is a beautiful, well themed, romantic (especially at night for long, slow walks holding hands!) resort!
good luck!
EDIT: I used to be the type who was up at the butt crack of dawn and hitting the parks hard... all day long.. and then going to Pleasure Island or Downtown Disney at night and was NEVER in my room (when I went with my girlfriends and was single

) but now that I'm with my DF... the last time we were at WDW we would wake up and have some breakfast at the hotel poolside (ASMu even!) and I realized, wow!, it's really nice to lounge around and just enjoy the resort!