First of all you might want to visit the Ukulele Underground Forum as there have been several threads on this topic:
http://www.ukuleleunderground.com/forum/
When I started on Uke a couple of years ago, I ended up with a tenor, as it was more finger friendly than either the soprano or concert. I also tune with low G rather than the standard high G tuning, because I play fingerstyle tunes--it gives me the same intervals as the top 4 guitar strings, just a 5th off. Some guitarists prefer the baritone, since it is tuned identically to the top 4 guitar strings.
I would say that in the decent instrument category that Pono and Kala seem to be the brands most often in the price range you have mentioned.
For a step up (probably to the +/- $800 range you get into some real quality. I have a KoAloha tenor which is a superb instrument. Kamaka is likewise a high quality instrument. Kanilea and Koolau also get excellent reviews.
The following Ebay dealer is widely respected and you can check a lot of instruments on his site:
http://stores.ebay.com/Musicguymics-Room
I will personally vouch for Noel Tardy at UkeLady music:
http://www.ukeladymusic.com/index.html
Hope this helps and welcome to the world of Uke.
Jon