I'm also going to say live plants. I've got 3 small, low-tech tanks, one of which being 2.5 gallons, and after trying both silk and live plants I definitely prefer live, and will only be using the silk ones as placeholders until I can get some more live ones! I've had reasonable success (i.e. nothing has died, haha) with anubias nana (though any variety of anubias is good) java fern, a potted crypt and some floating water sprite, so the above suggestions should work well for you.
Live plants also look worlds better than any kind of fake plant.