You don't mention what you currently ride or what you're really looking for. Depending on what you'd like as your end result, starting with the 8-speed Sofrider is a good move, since it can serve as an excellent base for a number of upgrading departures. Let's say you want a fast road bike. If you've already got one you can simply transfer your existing components & wheels over to the Sofrider frame. Failing that, you can upgrade incrementally, as funding permits.
Aside from a pair of 26 x 1 slicks, perhaps the easiest upgrade is installation of a double chainring. 1st, get a used double chainwheel set from ebay or Craig's List. This and a set of 5 chainring spacers (approx 1mm thick) bolt directly onto the existing crank in place of the 44T ring & chain protector. Just add a left hand shifter & front derailleur to complete the package. Of course, you could also just swap out the existing set of cranks for a triple, replace the shifters with a 3 x 9 setup & get a 9-speed cassette.
You may decide you'd like to upgrade to disk brakes. It's a bolt on at the front, since the mounting brackets are already there on the fork, just change the cable. Unfortunately, today, you'll need a custom adapter bracket at the rear. This may change shortly and be readily available aftermarket, making it more of a direct bolt-on upgrade. However, disk brakes allows for very quick wheel changes -- you could have a set of 700c rims for fast road riding & also a set of fat-tired 26 inch rims for touring. The Sofrider is quite versatile.
