So how many people are using subwoofers


with full range floorstanders? I need just a little more bass weight out of my system and have vascilated between REL subwoofer or upgrading my amp from Conrad Johnson MF-2200 to an MF-2500. 60-70% of the music doesn't need a sub,but that other 30% keeps me off balance. Is the amp upgrade going to give me more bass weight (along with other benefits) or should I just go for the sub? I think I know the answer but would like to hear other opinions.
existing system=
CJ PFR pre
CJ MF-2200 amp
Theta Miles cdp
Silverline Sonata speakers
Homegrown silver lace ic's
MIT-2 bi-wire
artemus_5
Subs are good...the more the merrier.  They take the power required for lows away from your amp and regular speaker so that they operate better, cleaner, etc.
I'm using two Rymthik F12G's and couldn't be happier, they were easy to place in the room and fine tune (altho still a work in progress) and the subs  do a great job filling in the bottom end.  I have never been a fan of subs in a two channel setup, but now accept them. 

A second for the Rythmik F12G, a sub made expressly for music reproduction. The G in the model designation is for GR Research, whose designer/owner Danny Richie collaborated with Rythmiks Brian Ding on the design of the woofer (a paper-coned version of Rythmiks aluminum one, for increased low-level resolution) . The Rythmik subs feature a Servo Feedback loop of a new type, differ from (and superior to) older SF designs. For DIYers, the woofer is also available optimized for Open Baffle use, and two of them installed in a Dipole frame is THE sub for planar loudspeakers. Seriously good!

I'm using two rel s-2 they just help you get the lows better. Deeper and it also help the midrange

I am using 2 Vandersteen 2wq subs with  Gradient revolution speakers (passive version ) with good results.