Why not buy it right now ?
This stuff about waiting for the super-mega-edition-gold of a movie and never buy it is really a drag, for example I'm contemplating buying star trek dvds only now, that they are putting out some quality material with good remastering and top grade extras, so yes, I'm happy not to have bought all those initial "pack the movie, put up a menu and an interview with the cast" deals, so I made a good call to wait on this case.
But with boxed-sets I think its a bit different, they are not likely to go and rebuild a whole movie just to fit on the box-set, in most cases they just pack the movies on a single box with the only value to you being the low total cost of the package. If thye are really going for it, an extra cd is the most likely thing to happen, so this is the only situation you say "ah, hell, damn I should not have bought it, oh well"
Going back to Indy, you say, "in 3 years time" they will relaunch a new box-set, probably. But most likely is for them to make a quality Indy 4 - 2 disc release, just because the new movies are made with a bit more of insight that they are going to be released on DVD markets and so add-on material is now not a question of "ok, what do we have here that can go on the dvd", but more of an active effort to provide that material. The StarWars Ep1 extended making-of is a wondeful example of just that, one of the best making-ofs I've seen, just because it was done right there on top of it, everyday, everytime, not some random making-of-shot intercalated with post production interviews.
Back to the question, if you have a PC, why don't you consider to buy a CD-ROM player ? It makes for a good mid term solution for your DVD viewing and collection efforts.
As for buying the november indy box-set, well, personally, I will buy it right now because like you and all the others here, I'm an Indy Fan, and they are the best movies of all time. I'm not going to wait another 3 years to save some bucks when, finally, the movies that went through my mind when DVDs come out are finnaly shipping!!!