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
128x128artemus_5
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. 
I used a single REL Q150e (150 watt 10") for years with no need for a digital room correction sound nanny (I think they can cloud things with more crap in the mix, plus my largish room has a tall sloping ceiling so it sounds good anyway) as I turn it up or down if needed (easy, and not so often). The mains run full range of course (a REL thing) and it all sounds amazing…got a second REL recently (Q108 MKII) from the same vintage and man…simply better…"charging the room" is part of what they do as that sense of low ambience is part of the natural sound of the world, and should simply be there. I turn the subs down to demo this for friends and they agree with me, and think I'm a wonderful person with great taste.