Ah arwenthecat.. if only you knew how many months I spent researching just this problem and then practically testing a whole bunch of units

. Well let me save you some trouble. Soundbars, even the better ones from Samsung, actually aren't all that good (I had the HWC450 for awhile and that one even did DTS decoding, which is rare at the £200+ price point).
Sure they provide a good depth of sound, assuming you can get them to work (had lots of problems with getting the things to function properly and sound right), but the width of sound and sound separation between your left and right ears will always be poor. No amount of clever software tricks and speaker angling can make a centralised soundbar sound like a good pair of headphones.
In the end I gave up and went for a Q ACOUSTICS Q-TV2, which straps to the back of your TV and actually does so in quite a clever, mostly unobtrusive and flexible way. It can't decode DTS but that doesn't really matter for 2.1 setups anyway and it does have a digital audio input so the sound is still extremely clear when passed through your TV.
I did have a slight issue early on with getting the digital audio to work but luckily the manual explained some of the quirks with this and I was able to resolve that (you sometimes have to disable DTS outputs on your device and set them to 'normal', even if they're being passed from a Sky TV box through to the TV first).
Otherwise I'm quite impressed. The sub-woofer does an unbelievably good job given that it doesn't vibrate and the side pod speakers are flexible, so you can angle them in such a way to get that headphone style quality. We watched Avatar with the set turned up and the audio made normal cinema sound (the one you pay to visit) seem tinny

.