I have always liked Samsung and Viewsonic, but Benq has a decent reputation too, but so does LG. Note that while there may be dozens of monitor makers, there are only a few display makers. So there is often little difference in quality of the image. And all brands have some models that are better then their other models.
If you are used to using two monitors and planning to move to just one (even if a large 24"), I think you will soon be disappointed. I don't think I could ever live with just one monitor again, regardless their size.
For years, I ran with a mixed mash of monitors. When I bought my first 17", my old 15" became my secondary monitor. When I bought my first 19", my 17" became my secondary. When I bought my first 22" widescreen, my 19" became my secondary.
Then I realized another problem - though I already knew it, it hit home when I tried to buy another 22" so I would finally have two matching monitors. Monitor makers redesign models almost on a yearly basis. I could not find, except used, a matching monitor.
So I bit the bullet and bought two new matching 22" Samsung widescreens at the same time and have no regrets. Both are at 1680 x 1050. And sitting no more than 24" away from them, BluRay HD content is gorgeous. That said, if I want to watch a movie, I do that on my home theater system with a big screen so others can enjoy the show, and the genuine high fidelity audio too (even the best surround sound computer speakers cannot come close to competing with a half-way decent home theater audio system - and with audio reproduction being my first love in consumer electronics, mine's a bit better than "half-way decent"!
Sadly, most monitors and TVs are adjusted at the factory to look good on the showroom floor under bright lights. So while you can compare features and aesthetics at a store, getting an idea of the image quality is hit or miss, and may be a miss once you get it home. I recommend you visit your local retailer, write down the model numbers of those you are interested in, then go home and plug the numbers and the word "review" into your favorite search engine and see what the hardware review sites say.
Do NOT pay too much attention to user reviews. For one, happy people don't complain. For another, users don't have the qualification or equipment to perform a good review. And most importantly, they don't have comparable models for proper side-by-side comparisons.
I scan through user reviews at places like Newegg and look for trends - for example, if many of the reviews report the exact same
problem, then I will take that into consideration.
Oh, another thing. I always look for monitors with height adjustment and for some reason they are hard to find. For one, I like to adjust the height of the monitors for proper viewing rather than the height of my chair. That seems like common sense to me so I fail to see why monitor makers don't get it. Also, I have a hutch on my desk and most fixed height 22" and larger monitors will not fit under my hutch.
Finally, if you do, or rather when you do
get a second monitor, having a wide bezel (the frame around the actual display screen) creates a very wide gap between the displayed image. Many monitors have a very wide bezel, either for looks, or to house controls or even speakers. But there are some monitors that have a thin bezel (my Samsung's are about 1/2 inch) so side-by-side, the gap is pretty small. Just something to think about.