If you decide you enjoy singlespeeding (as I do) then you might want to junk the tensioner and invest in a White Industries ENO Eric's eccentric rear hub and get it laced into a decent rim. Used in conjunction with a WI freewheel I've found them to be very good. Bit pricey I guess but worth it.
It also means that you can still ride your favourite bike with the vertical drop-outs as you can tension your chain by rotating the rear hub and then locking it off. No forking out for a s/s specific frame or frame with horizontal style drop-outs/track ends.
Don't bother trying any 'magic gears', before you know it your chain has stretched and just when you least want it it starts slipping when you're at your furthest point away from anywhere (sod's law states this I'm sure).
I use a 2.25:1 ratio (36:16), it's quite hilly nearby but not overly long hills.
You'll find that the longer you singlespeed the stronger you get, it always seems that you're kicking out about the same power and suffering the same but when you check your times you'll find them quicker.
If nothing else... enjoy!