I'm not a massive fan of online multiplayer.  I love a massive, immersive single player experience.

The best single player shooter this generation has easily been Bioshock.  This is for the simple reason that it popularized some awesome stuff that System Shock had done, and was designed to be a deep, fun, immersive single player experience.

Now out of Gears and Cod4, I'd say any given moment of CoD4's campaign was marginally better than any corresponding moment in Gears campaign.  But Gears's campaign was better overall for the simple reason it lasted longer than 5 hours.  Quality is more important that quantity, but when quality is close, I'd rather have more of it than less.

Gears campaign wasn't long enough (8-12 hours) but at least it was approaching acceptable (12 is fine, but on co-op I'd finish it in 9 which isn't fine).  But Activision now has the impression that putting out a shooter thats advertised as having a campaign which turns out to be 5 hours long is ok.  But thats ridiculous, its not ok at all.

Its all well and good to expand multiplayer options, but it shouldn't be at the expense of single-player. 

Starcraft be honest now. You are not a huge fan of online multi-player because you have no skills and get pwned every time by 12 and 13 year old Americans.

Gears of War 2 will be an enhanced visual upgrade of Gears 1 with new levels. Single player campaign I guess around 12 hours duration.

COD 5 well it is made by Treyarch and do not hold your breath on that game. COD 3 sucked big time in more ways than one. 

Thats perfectly true.

But its also because getting good at it takes time and a super-strong broadband connection that in Australia is effing expensive. 

I found the CoD4 single player a perfect length. I am not a hard core gamer so it was nice to finish a game. Most of the time I only get a third to half way through and get bored of the game.

cod4 campaign was way too short! But I heard it was cut due to media limitations (dvd), not sure, but it sounds reasonable. So, I would not expect very much longer campaigns in the future, at least for multiplatforms.

I hope these campaigns are longer as well.

I think Gears of War was decent length but had to vague of a story. I hope they explain more in single player.

There is practically no way that these franchises will focus on their single player campaigns. They may be slightly longer simply because we can expect increased financial investment, but these games are selling because of their multiplayer.

Or put differently, the extra millions of dollars poured in to these franchises will be largely invested in multiplayer functionality, not single player campaigns.

Well, they should have financial inititives for making single player campaigns. Though, most people are interested in multiplayer, there are many, like starcraft and me, who are more interested in single player campaigns. And I'm not afraid to admit that it's due to the fact that multiplayer games are not funny, unless you are good at them, which means you have to have a lot of spare time, which is not usually the case for professionals.
I won't buy games with very short single player modes anymore.