Invisibility isn't so bad in a combat situation, since you pop up as soon as you attack. It's improved/greater invis that's the bear. Me, I just banned that one. Too much hassle to work around it.
Hmmm...
see invisibility
blindsight
deeper darkness (everyone is "invisible")
blindsense
scent
really high spot bonuses and listen bonuses
glitterdust
environment: thick mud, standing water, snow, layer of dust, room filled with cobwebs, bead curtains, rain, lots of bells on strings, etc...
I also really like the idea of keeping players ignorant of the precise positions of their invisible companions. Makes communication and coordination a more interesting challenge.
I would use any/all of the above rather than banning
greater invisibility. I just don't feel that invisibility in general represents an insuperable obstacle. My current sorcerer makes liberal use of
invisibility and
greater invisibility, and casts
see invisibility daily. Yet I still spend less than half our fights invisible, often b/c I don't want to waste the spell if I feel we can take down our enemies quickly or if another spell will be more useful. Like last night we were ambushed by an invisible lich. I saw him, but couldn't warn the party or stop the lich before he blasted us. So the next round, rather than turn invisible myself, I just grappled him with
telekinesis. That worked so well that I spent the whole battle using that spell. I never had time to turn invisible. The duration of those spells (1 rd/lvl for greater and 1 min/lvl for the lesser version) means you don't spend all day invisible, so preparing the whole party to benefit is only practical if you are able to spend a minute preparing for a major battle. The rest of the time,
greater invisibility is only useful to keep my sorcerer (at level 10, AC 12 and 43 hps and weak saves) alive and kicking. Its useful, but not a game-breaker (IME).
Ozmar the Invisible Sorcerer