Sony & Panasonic give good sound quality, Samsung variable. By that I mean acceptable, realise the low end is impeded by the TV structure. Samsung on some models is laughable, but that is because they are 2x 3W whereas the others for a little bit more give 2x 10W (the difference is the Samsung starts rattling or booming before you get to an acceptable sound level, they aim small ones at bedrooms).
Sony, Panasonic & Samsung can have similar picture. What I really mean is they may all use PVA or IPS panels, rather than TN. The problem with TN panels is 6-bit colour, poor viewing angle, low contrast despite drivel 20,000:1 ratio, and pretty miserable performance with black/night scenes re films.
Warranty is important, but beware cost. An LCD panel has a few parts: PSU, Inverter, Decoder, Backlight & Panel. If the panel fails (and they do) that is the most expensive part and the TV is scrap. LCD will not last as long as CRT, and PSUs in particular are likely to be a weak point (LG & Samsung perhaps particularly from experience with their monitors included rebranded). A free 3yr or 5yr warranty is worth having, but paying =A3150 for it is not. I would not accept a 1yr warranty on a =A3300-400 TV, I would want a minimum of 2yr and would pay =A330 for an extension to 2yr but not more than =A350 for an extension to 3yr. Some TVs come with 3yr warranty, others can be had cheaply with a longer warranty (check Richer Sounds for their offers).
Beware the codes. One TV such as 6000U may have a TN panel, a 6000V may have PVA panel, a 6000T may have IPS panel - and the price rises accordingly. So always check what is *inside* the TV where different panels are available (Sony).
Read the reviews broadly. Amazon & Argos are handy - but always start with the worst reviews because they tend to be written by someone with a clue, such as "the sound sucks from 3W speakers" or "this model is now a TN panel which is pitch black for dark films and has horrible spotlighting in the corners re backlight" or "the thing takes 30min to give a decent picture and then it suffers from motion blur" (this is what the better chipsets avoid re jaggies and judder).
When you get it, go into the menu and turn down "sharpness" and similar filters - they will give everything a sharp halo edge when you want a soft image to hide the "sized like lego pixels". Remember a
26-40" TV is still a very low resolution panel compared to what a monitor would have, so too huge in a tiny room can work out badly.
A 26" TV is fine re size for someone not bothered about TV (me!), however for films 32" is actually a lot better even in a small living room. Going to 40" requires a fair viewing distance, LCD is still not quite CRT.
For anyone planning on being "modern", the number of HDMI ports matters (2+), plus Freeview-HD unless you want another box to fiddle with. Check on last years model and shop around, bargains can be had but there are a lot of people looking so things go quickly. Always check what spec you are actually buying. Amazon UK can be useful on pricing, because they tend to walk prices down for a time - wait too long and they "return back up and begin again". There is usually one good offer on there which is difficult to beat, the downside is their warranty is costly - always check John Lewis, then check around because other places do undercut enough to make the warranty less critical or offer a 2yr/3yr at minimal cost (=A325-30).