Over a month late to the party I know, but then I don't get out this way often
I've actually just been on a major indy RPG binge and spent wayyyy too much on some great stuff. The problem I've found is convincing people to play the weird and wonderful games I've got
Anyway, indy games can be tricky to suggest because they vary quite a bit from the normal pen and paper games. Some are GMless, some are more about group story telling, others delve into the darker parts of the human condition. Is there any particular genre you're interested in? That could help in terms of suggestions. But I'll throw a few titles at you based on the list of games you mentioned in your post.
If you've played D&D and like fantasy then I'd highly recommend the Burning Wheel game - its a really nice intro to the world of indy games as it doesn't stray too far from the system and play mechanics you'll be used to. The basic set comprises of the Burning Wheel rules and a second book called the character burner. Both books are paper back novel sized. A couple of extra books have come out: Monster Burner (for creating monsters), and Magic Burner (you guessed for adding your own magic flavour to the game). The Burning Wheel is all mechanics and no real setting though - so you'll need to roll your own
Of the ones you listed I've got all but the mountain witch one: Dogs in the Vineyard I can highly recommend, don't let the Mormon like religious trappings put you off. Its more about you being cowboyesque law bringers in a land of tightly repressed people. The conflict mechanism is wonderful and has you rolling a pool of dice that has to last the entire conflict (when you run out of dice to use before the other guy you either need to raise the stakes -eg: go from talking to shooting - or lose). I have Primetime adventures but haven't looked at it yet - I have heard its one of the best and easiest to get new people into but I can't confirm that. My favourite is Don't Rest Your Head (I've also got the Don't Lose Your Mind suppliment) its a dark game with very simplistic mechanics that are linked very nicely to your characters state of mind. You play insomniacs who can use their exhaustion and madness to power their 'supernatural' abilities but at the risk of falling asleep (which is when the nightmares get you) or of going mad. Its set in the Mad City which exists only for those insane or exhausted enough to be Awake and find it - the city is a lot like Neil Gamen's Neverwhere setting.
Universalis is closer to a collaberative story telling game than an RPG but it looks fun (not played it yet). It uses a coin based mechanics that has the players pay for story elements and things that happen. The in game coin economy is based around conflicts (that generate the most coins back to the playes). The rule book is quite small but dense and I've read it a couple of times and still not 100% sure I've got it all. But I'd love to try a game of it one night. Generally the players don't play individual characters but instead take and give control of story objects (can be characters), add 'facts' to the world, set scenes and describe outcomes by spending the coins. Conflict is resolved by dice that come from story element traits (eg: a characters gun) or purchase by coin.
If you like superhero games I can highly recommend Truth & Justice - I've run a couple of games of this and I found it easy to come to grips with and gave enough meat for my players to feel comfortable playing. You don't have stats/skills but have areas of ability - eg: Homicide Detective, this gives you the chance to roll on investigation, intimidation, gun combat etc, anything that a Homicide Detective would know. Add powers to that and you've pretty much got the character. In combat the first ability to take damage also generates a story hook - eg: if my Homicide Detective ability was the first to go down due to damage (you use your areas of knowledge and powers like hit points so they get worse as you take damage) then the GM uses that to generate a new subplot or story elemenet based around it.
Hot War is a great supernatural game set in London during the 60's but after the Cuban Missile crisis led to the launch of nuclear weapons and worse. The combatants used both nuclear and supernatural weapons to destroy each other. The characters play members of a semi secret organisation made up of military and specialist civilians tasked with dealing with the supernatural elements in a destroyed London. Gameplay is based heavily on character relationships and hidden agendas.
Fantomas already mentioned Spirit of the Century above - its also a good transition from more standard roleplaying to the indy side of the fence. I reallly want to run this one. It looks like a great set of rules for a Pulp game. It uses a modified version of the FUDGE system (based on descriptive terms rather than numeric values - eg: Average = 1 while Legendary = 8 - that you roll 4 FUDGE dice - 6 sided dice with 2 sides as (-), 2 as (+) and 2 blank that give you a total result between -4 and +4 that you add to your skill level - that is then compared to the target). The FATE system used in SOTC is less stats based instead focusing on Aspects that are phrases that describe aspects of your character (eg: My fists do the talking, or Raised by Wolves). You invoke an aspect by spending a Fate point (you generally get 10 of these at the start of a session) and it gives you bonuses to rolls - but the GM can also invoke one of your aspects for a negative effect that gives the player an extra fate point.
I've got another game that uses the Fate system from SotC above, called Starblazers, based on the old UK comic series of the same name (not the mangled US version of the Space Battleship Yamato original anime). Its a sci-fi game very similar in tone to SotC but with a bit more tactical and serious gameplay.
Damn, but this got long very quickly... sorry for the ramblings. Anyway let me know what you're intersted in and I'm happy to help. I've got heaps more I haven't mentioned so don't fret if you're intersted in something which isn't on the list