Ok, lately I've suggested that your hand selection on raising/calling raises depends largely on how many players you expect to see the flop. I also think there's another extremely important aspect, which can influence both hand selection and the way you play your hand: Who your opponents are.

Essentially, against a nut-peddler, you are looking just for some kind of hand (maybe none, but ideally something on the flop) where you are the aggressor. The nut-peddler is likely to lay down, and if he plays back at you, he probably has you beat. Against a LAG, you're looking for high-percentages on hands that you can call them down with and take down the pot.

Also, against a LAG who's going to keep firing, you don't need quite the same percentages because you are getting some implied odds--hence, you can throw in some hands that have lower percentages of hitting but hit the flop harder.

This being said, I've suggested a certain range for HU pots: Basically, any AA, any KK, any ds to reasonably big cards.

3-way, I think what you're looking more for hands that "hit" something like 25% or more, and I think a K-high flush is worth drawing to. Hence, probably being more restrictive on your AA, like AAss (obviously ds) or AA with 2 pair. Also KKds or ss is also pretty strong. I'm rather inclined, actually, to put any 4 distinct cards ds to the A and the K in this group--like AsKc2s3c. Also, if one of your opponents is a LAG, I think you can put most of the "MP playable" hands in this group.

4-way or more, you're getting excellent pot odds, and the mere "any 4 cards" bonus in Omaha is high. Here, I think most of the MP playable hands are also acceptable in raised pots--on the stronger ones, you probably want to go ahead and raise yourself, at least with position.

One group of hands, however, I think is a little weak in 4-way pots or more: namely the pair wraps where the pair is lower than 88. Pairs below 88 are too likely to be bottom set and I think thus become a very weak feature in multi-way pots. Hence, I'm thinking a hand like 4557 is probably just not really worth playing even in a raised 4-way pot.

On these hands, I will say that I think having the actual wrap rather than a 1-gapper is fairly important. For example, on 4456, if you flop a set, all you need is a 3 with it to have a very strong draw in addition to your set. Or, on 4556 or 4566, the same (you just need a 3). but on 4557, a 5 with a 6 is significantly weaker because hitting an 8 no longer gives you the nut straight.