When I set up my 65 gal tank, low maitenance was the goal. I needed a home for my pleco, so indestructable was also a major consideration as he had torn up my previous attempts at planted tanks. I decided that bogwood and Anubias was the way to go. I got some pretty big pieces of already waterlogged wood, and absolutely covered them with a. nana, a. coffeefolia, and a. congensis. This meant that I only needed about 1 wpg of light, so I didn't have to spend a fortune on a light fixture. The only other plants are a bunch of salvinia floating on top, and I tried growing some water onions in a pot, but they don't do so well. There's also only a thin layer of river pebble for substrate, just enough to cover the bottom, so vacuming the bottom is a snap. For filtration, I'm using 2 FLuval 3 Plus filters, one on each end of the tank. The tank is very fully stocked with a bunch of SAEs, Rainbowfish, an Angelfish, and of course the Pleco. I havn't had a death in that tank in over 6 months, since a 25 hour power outage that made the tank temps drop to below 70 degrees and killed the other angelfish. I do not do regular water changes on this tank, I pretty much just leave it alone, until I feel like it (usually once a month or so), and then do a 40% water change. There's no algae, though I did have a period of about a month of green water so thick I couldn't see the fish unless they were three inches from the glass. This happens when I first set up almost all of my tanks and goes away once things have settled.
Here's a picture of the finished tank:
http://www.dartmouth.edu/~illustrae/Aquaria/pictures/pict0058.html
I think hairgrass would look very nice, though I've never had luck with it myself. I have found many crypts to be hardy, low maitenance, and they come in a ton of varieties that should suit any need. C. spiralis is one of my favorites, and grows tall and straight like jungle vals. C. balansae or C. retrospiralis have wavy leaf edges and red/bronze coloration that can be nice. C. wendtii is a smaller crypt that comes in several color morphs and looks great clustered around hardscape like rocks or wood. Crypts don't require any maitenance once they are established: no ferts, no CO2, no trimming, no nothing.
I'm not a guppy fan at all, so I can't really comment on your stocking idea. If it were my tank, I'd go for something a bit bigger. If you really wanted a livebearer, platies or swordtails are my choice, as they are larger and less likely to eat their young. Some of the larger tetras are quite hardy and a school of 6-10 of lemons, diamonds, or serpaes would be nice with a centerpiece fish of a gourami or something. I also can't reccommend rainbow fish highly enough. They are pretty hardy, aren't picky about water parameters, and come in tons of varieties and colors. A cleanup crew of a bunch of Amano shrimp and maybe a few nerite snails might not be a bad idea to clean up any leftover food and control algae.
Wow, that was longer than I intended. There are tons of possibilities for a tank like this, and they don't have to be hard to maintain at all.
If you want gouramis to breed, adjust the spray bar and get some cork bark to create a still water surface in one corner.