Replacement Speaker Problem

The majority of stereo loudspeakers are a nominal 8 ohm, though the
impedance of most designs will vary somewhat with the frequency of the
signal they are being fed with.

If you use a 6 or 4 ohm loudspeaker, the amplifier in your television will
have to supply more current (amperes) to the loudspeakers for a particular
level of power. If the amplifier can't do this (because it isn't powerful
enough) then potentially damaging distortion can be created.

 Because of this, lower impedance speakers are often termed as "more
demanding" and as such are not usually recommended for the relatively poor
amplifier circuits found in most television sets.

snip

There really isn't much difference (apart from particular technologies like
THX and dipoles).
Manufacturers may call a particular product line "home cinema" speakers for
marketing reasons as much as anything else.
What you need to do is find a good dealer (not the multiples of Comet Dixons
etc) who can demonstrate different speaker systems to you.

As a starting point for finding a decent pair of speakers have a look at
http://www.mission.co.uk/
http://www.bwspeakers.com/
These are two British companies that make a range of speaker systems across
most budgets and aspirations.

Buy a mag like Home Cinema Choice http://homecinemachoice.com/
HiFi Choice http://www.hifichoice.co.uk/
Have a read through and find something that suits your pocket, then find a
dealer and see if they suit your ears.

Although the big Toshiba set you have has Dolby surround built in why not
think about an external Dolby digital amp and speaker system! The
improvement will be immense.

Thanks for the explanation, it makes a little more sense now. With that in
mind, would I be better off therefore buying some speakers intended for a
hi-fi instead of home cinema speakers?