On a recent evening I decided to walk along South 1st. St. (South First) between Oltorf (on the south end) and Copeland (on the north end) to take in what I've always perceived as a funkier vibe than either South Lamar or South Congress. This area of South First is narrow, with smaller buildings and more trees than either Lamar or Congress, and that plays a large part in the different feel of the area.
If I had to describe South First in a nutshell I'd say that it's an eclectic mix of the fancy and funky, with high profile restaurants like Sway (too cool to even have a sign!), art galleries and a few different food trailer spots that feature good food a reasonable prices. This area of South First is a good walking area but there isn't a large amount of foot traffic in the evening, a fact that makes for nice, relaxed strolling.
As you can see there are lots of cool sights to see and places to stop in on along South First. I plan to go back there soon during the day to stop in on some of the galleries and try a variety of the food options.