I did a conversion. A few things to consider:

1) How are your rear dropouts? Vertical? Semi-horizontal?
2) If vertical, are you going to go magic gear or tensioner?
3) If its going to be a commuter bike, will you want to commute on 23c tires? How much room does the frame give for bigger tires?
4) Gonna use the wheelset you have now? If so, it makes getting the chainline right easier (since you will probably use a freehub SS kit, which allows a lot of lateral adjustability)
5) Are there a lot of hills near you? This might affect #2.

Here's mine - used SRAM s100 48t crankset and DMR bikes rear conversion with a 16t cog.