Here's my take...
I play a hand when I think it's profitable to do so. Sometimes this leads to playing a lot of marginal hands, sometimes it leads to playing super-tight. Meta-game considerations aren't high up on the scale for me, that is, I don't play lots of hands just so I can get paid off when I make a hand. However if I happen to have played a lot of hands and played them very aggressively I am aware of this, and try to figure out which of the players have adjusted to my play, and then I try to readjust to them. You just kinda go with the ebb and flow of the game and your cards.
Oftentimes, especially in a shorthanded game I raise with marginal hands in late position to isolate the bad limper who I want to play with. Some people might regard this as LAG play, but really it's only a matter of playing a profitable situation in the most profitable manner. Profitable button play for me at least includes a lot of weakish holdings.
whitelime writes more about this in
his post.
Raising suited connectors and stuff early is a slightly different story, in that it also serves to widen my hand range and make it harder for my opponents to play against my big pairs. Still, I don't raise UTG if I don't think it's at least neutral EV in the current game conditions. If you get called a lot by bad opponents anyway, you have less need to mix it up. If you have been playing few hands, and the table is also playing tight, then you have a good chance of stealing the blinds. Also your opponent are likely to misread your hand, which leads to profitable situations.
So I don't really care that much about LAG or TAG play as such, I just try to recognize profitable situations. The so called solid players see fewer situations as profitable, and so they play fewer hands.