The donation model won't work for most developers. It hardly works for Dwarf Fortress even; it was several years before Toady One was making enough to not be living off savings, and even still he's barely making a living wage. Premium account sort of things I can't see working well with indie games. Free demos are of course very good and should be released for almost every game, but that's about as close as one should get to a free/premium dynamic. Microtransactions wouldn't work for a vast majority of indie games, as those are only really applicable for games in which DLC can be easily added and adds value or for social games. However, if it is a social game, microtransactions with premium accounts granting access to stuff which you would otherwise have to pay for with microtransactions would probably fare relatively well (DD:O's business model). I'm not entirely sure how profitable ads would be for most games; they also have the added downside of needing to find several advertisers willing to pay, which I would imagine takes a bit more business sense than the other options. The indie bundle model did make quite a bit of money, and as such is a good option; the trick to making it work is getting the word out to enough people. It depends on game journalists and forums to market the game for them.
As for what I would do if I were to market an indie game: Steam. The first week or two after release, keep the price at a decent amount. Probably $10 or so for most indie games, $15 to $20 for a larger one. After that, work out a sale on Steam for something like 60-75% off. The first couple weeks, any interested in the game from the start will probably buy it shortly after release for the normal price, then a couple weeks later the sale hits. You then have your game plastered on the front page of a service used by millions of gamers every day for a price low enough to encourage people to buy it upon impulse. Preferable time for such a release would be a time period in which there are relatively few competing sales and after a somewhat long period of time has passed since the previous really big Steam sales (the two in December-January and June-July).