Most PC speakers have the volume control on the speakers themselves, so to control volume without getting up to adjust the volume control, you would need a TV that has variable, not fixed, output for audio. This used to be standard for almost all TV's, but in the last five years is becoming much less common, especially among the more high-end television sets. My high-end Panasonic has fixed outputs, my low-end Sharp will let you select whether audio out is fixed or variable. In my bedroom, I am using a PC soundbar from Altec-Lansing that was about $79 three years ago. Sound is better than the TV and it has a second input for my digital music player. This is nowhere near Hi-Fi, but not bad either.
For a main TV, if you want to keep things simple, I would recomend either a soundbar or small 2.1 system. I'm not sure what is out there currently on the 2.1 side other than Bose's small system that you can find inside Target or Best Buy. I know several years ago both Denon and JVC had systems with only two speakers, no sub-woofer, that sounded pretty good. Not sure if either has anything like that currently.
As far as soundbars, you have a world of choices from very inexpensive (cheap) to quite expensive. On the low end you have last year's Vizio vsb-200 which I believe can be purchased for less than $100 new at Wal-Mart. This unit offers decent bass and excellent voices without the addition of a sub-woofer. Going up in price, Boston acoustics offers a unit with really good sound quality that sounds very good with 2-channel audio also (around $300). Between $200 and $300 there excellent units from Sony, JVC and Panasonic. Based on reviews by Daveyo, the JVC may be my next purchase in the soundbar category.
If you want extremely high-end sound, KEF and B&W offer soundbars that have true 5.1 channel sound from five discrete speaker channels within the soundbar. These cost well over $2,000 and require a receiver of 5-channel amplifier as they are not self powered like the other choices mentioned above. I have never laid eyes on one of these, much less heard one, but have read reviews from trusted sources that say the sound is truly excellent as it should be from companies with their reputation.
Finally, there are the Yamaha Sound Projectors. These are very special soundbars that have a world of simulated surround modes and many users say they never want to listen to anything else. I have owned one of these units and the sound is good and very natural. I personally never found a surround mode that pleased me and was never happy with the headroom and dynamic range of the unit so gave the unit to my son. I do not mean that as a slam on the Yamaha as the tonal quality was excellent, it simply was not the correct unit for my home theater.
My personal recommendation is to start at the low end of your budget and purchase from a retailer or on-line source with good return policies. When you find a unit that pleases you, keep it and enjoy.