I'm a newbie as well.
I ordered the skyhawk 66cc kit from Spookytoothcycles. Spooky tooth has been great, they do sell full kits including the bike starting at 450. I had to go cheap though, I got an old Schwinn Collegiate from craigslist for 15 dollars. I live in an urban area, lots of cars, but also lots of hills so I've found that the sidepull brakes on the collegiate are woefully inadequate. I'd recommend whatever bike you land on get one with good front and rear brakes, at least V brakes, maybe disc. Although beware of cheap disc brakes. A walmart schwinn cruiser with 7 speeds, and front and rear V brakes sounds like one good way to go for urban motorized use. I got the 2 in one brake lever so that both brakes can be pulled with your right hand leaving the clutch lever to your left hand.
I think no matter whose kit you order, if it is what folks round here call the Happy Time, or China Girl based kit be it Skyhawk, Starfire, Power king etc, there are going to be some questionable parts. The nuts and bolts are cheap. But at the very least, replace the nuts and bolts on the chain tensioner. It is a two buck fix that goes such a long way. Otherwise the stock bolts will strip, and you will not be able to tighten the tensioner so that it is safe. There are lots of threads on here about the tensioner. Many folks have custom fixes that look really smart. But you want that thing on your bike so solidly that you can't move with your hands no matter how hard you try. This will help with keeping the thing from coming loose and wrecking your spokes, or allowing the chain to derail. This is also assuming you align it correctly which is another top priority for safety's sake.
Also the carb gave me some grief for a little bit. It was a huge mystery to me how it worked but I just had to get comfortable with its guts and taking it apart. In my case the slide was stuck because I had tightened the carb onto the engine too much resulting in the thing contorting making the throttle stick. Just something to watch for if you get a 66 skyhawk kit.
Here's my ride so far but monday a springer fork with V brakes is arriving: http://www.youtube.com/watch?v=Xwr5RlxJ9i4