What are you using at the moment? Does the speaker have to be a floorstander? What size is your room?
The Quad system is a great performer and can pretty much drive any speaker - I have used the 909 driving KEF Reference 201's, which are hardly an easy load. Speakers are always a personal preference, so a demo is advised once you've narrowed down what you are interested in.
Personally, I'd rather save a little more, as there is a huge selection of speakers in the £1,200/1,500 price point - because of price rises, I feel there aren't that many real quality floorstanders left. Top quality manufacturers like Proac, PMC, Dynaudio and Spendor all start their floorstanders in this sort of price point, and are a huge step up from those in the £500/1,000 price point. I'd look at
Spendor A5's,
Proac Studio 130's and
140's,
PMC GB1i's,
Dynaudio's Excite X32's, as well as
Monitor Audio's GS20's. For bass, I'd particularly point out the Proacs, Dynaudios and MA's, although from what you say you may find the Dyn's a little overpowering. Obviously all these speakers come with foam bungs to tailor the bass to your room in case of any serious problems. I would also look at the
ATC SCM19's, which are more room friendly due to using a sealed cabinet, but still retain a pretty potent bass. The
SCM11's are within your stated price point, and would be my first choice based on your requirements.