I think Klesko is a big key to Giants success this season.  If he really is back to the Klesko before the shoulder problems he's a 900+ OPS hitter (even with the problems he was still better than most Giants hitters, he was an 800+ OPS hitter), he'll be a very capable replacement for Bonds in LF when Sir Bonds is resting, and he would boost the lineup greatly platooning at 1B with Aurilia (pushing Aurilia to 3B if Feliz is scuffling, so either Feliz is hitting well, around .790 OPS, or Aurilia is playing and hitting over that, or the two battle to keep 3B).

I think the starting rotation can be much better than just fine.  Zito and Cain are both capable of ace-type performances, but at worse they should be good #2 starters.  Lowry and Morris have shown that they can reach #2 performance when they are healthy.  Ortiz is the #5 spot where, as a study on The Hardball Times showed, most teams just sucked there, and if he can even provide a #3/#4 type of performance there, that's better than the majority of teams out there, and if he is back to old Ortiz standards, as his spring training seems to indicate, we will have a heck of an advantage in that spot.

The bullpen is worrisome but I think the starters we have are capable of going 6-7 innings regularly, and thus you won't be going to the middle relievers as often as we might have before.  That means it is just the setup men and closer who we should be concentrating on.  

Benitez has been taken over by a doppleganger and is actually pitching very well, dominatingly well.  Molina is working with him to reduce his pitches thrown per inning, meanwhile Bochy wants to use him more than an inning at a time, perhaps start him off in the 8th, which the reduced pitches would help greatly with.  I like Kline and he pitched very well the first half last year, but poorly in the second half, and that disappointed him, so he said in an interview, so he worked harder to be in better shape - middle age lowered mentabolism hits everyone and he's finally acknowledging that and working on it.  Chulk and Correia I think will be fine as the rightly set-up guys.

Using the numbers sharksrog used, the Giants scored 4.6 runs per game last year - I think this year will see an increase because the lineup is full of vets who can be expected to hit in the 700 OPS range, plus last year had a lot of sub-700 OPS - Finley, Winn, Feliz (2nd half), Alfonzo (after first month), 1B (not sure if sub but definitely sub a lot over what the average 1B does, which is the best hitting position).  

And I really like Roberts as the tablesetter, first true leadoff guy since Butler (OBP and SB) and with all the Rubic's cubing you can do with position players (there is a scenario where Bochy choses between playing Linden in LF or Feliz at 3B, shifting people around as necessary), you can play who has the hottest bat, whereas last year, if an infielder was out, you had to play Vizcaino and if an OF was out, you had to play Finley (well, didn't have to but did).

However, let's assume only the 4.6.  As I noted, I think the Giants rotation is capable of #2 performance overall.  That's at worse 4.20 ERA (Cain and Zito probably under by a bit, but Lowry, Morris, and Ortiz over by a bit, I think this would be middle ground for the group).  That works out to a 89 win season.

My thinking on rotation, probable worse they can do:
Zito:  3.80
Cain:  3.80
Lowry: 4.40
Morris: 4.50
Ortiz: 4.50

That's 4.20 average.

Zito:  don't see why predictions end up with higher ERA than last two years when he's moving to NL and there's a pitcher hitting 3 times and they don't know him, which I have to assume is a huge advantage since it is his curve that is the killer.

Cain:  given his clean bill of health regarding mechanics, I think it is pure speculation that he's "due" for tired arm.  His arm wasn't too tired when he was shutting down all those teams late in the season.

Lowry:  I think he'll do way better than this, but wanted to be conservative to make my point.  He was a sub 4 ERA starter when healthy.  Even when he was messed up last season, he still had his ERA in the low 4's until he had his elbow problems (probably due to changing his mechanics due to his injury).

Morris:  I think he'll do way better than this too, but again was conservative.  He was a low-to-mid 4 ERA until around the period when he somehow broke his rib.  Now that he's settled with the team (no overthrowing like he did early in the season) and healthy (hopefully), he should be able to deliver a pretty good performance in 2007, with only the injury bugaboo lurking, but with Lincecum in the minors, I'm not too worried.

Ortiz:  from all indications, he looks like the Ortiz of old.  The Ortiz of old delivered high 3, low 4 ERA.  Again, conservative.

I think I was conservative with all this and yet I come up with a 88 win season.  I fudge a bit there because I did not account for the bullpen, but given all the possibilities for higher performances from all the starters, I think my conservatism there covers for the bullpen's wide range of possibilities.