Read the FAQ at the top of the page. It'll answer your Qs.
I can't say which is best but I run the newer style Surly Singleator. I like it. You do have to get a 18mm (or 14?? can't remember) cone wrench to install it.dgangi said:What's the best way to convert my old Trek HT to a SS? It's not a SS frame, so I'll need something to keep tension on the chain. I know there are a lot of variations on those devices, but which is best?
This depends on your terrain. You can search single speed on ebay and find a kit by flashpoint_cycling that includes spacers and a cog for about 10 bucks. I decided to get an 18 and a 20 but it's a little mountainous in Central VA. I never really use the 32-20, but the 32-18 is a little harsh on days when I am not feeling so strong. If you are near the coast or someplace flat, you could probably pick up a 16 and an 18 and see what works. You just have to email the guy about getting two cogs.dgangi said:And what gear/cog ratio should I run? I'm a pretty strong biker, but this will be my first SS bike.