What do you want to use your rifle for?
If you are looking for a hunting rifle, the Ruger #1 is hard to beat at the price. I've found that the main variable with Rugers is the barrel. Get one with a good barrel and it will SHOOT. Get one with a mediocre barrel and it won't. Here's the good news... get one with a mediocre barrel that doesn't shoot and Ruger will replace the barrel with a good one (the repair department will inspect the new barrel and test-fire the gun to ensure the replacement is a good barrel) for free.
My favorite 'commercial' single-shot is the new Browning/Winchester 1885 in all its variants. Every one I've owned shoots great, they have a great 'feel' to the action, and in my opinion the American-style 'High Wall' is more attractive than the British-style Ruger and Dakota (although the Dakota is one nice-looking, fine-shooting rifle if you are looking to spend that much). Of course, I really like the original High Wall design but buying a good one is spendy. In reality, the repro High Walls, etc., are best-suited for target, sport, and varmint shooting for most people since they are somewhat more susceptible to inadvertant discharge than modern single-shots with safeties.
If you want versatility and performance at a good price, the T/C Contender and Encore rifles are worth looking at. My only gripe with the Contenders is that the action can be a bear to open, and with lighter barrels they are butt-heavy (and thus not steady for offhand shooting). People also brag up the NEF and H&R single-shots, and they do offer great performance at their price point.
