First, I want to say that I have read a lot of different tire threads in a few different forums and have been looking a lot of tire reviews online but I'm still a little uncertain about what I should do.

The bike I'm trying to figure out tires for is my 2010 Kona Jake the Snake. Right now I have 700x23 Michelin Lithion.2 on the front and 700x25 Specialized all-condition on the back - which I swapped off of my road bike after I kept getting flats with the knobby cyclocross tires (they're getting a bit worn out - I bought the bike used a month ago and they were the only things about the bike that was 'meh')

I want this bike to my "all-arounder" but it will primarily be used for commuting 14miles round-trip (all roads, some in pretty crumby conditions). I guess I'm a "fair weather" commuter, but I have done a few commutes in the rain on another bike, and am still riding most days in the low 30s/high 20s.

I'm trying to decide if I want to use this bike in occasional triathlons and century rides or if I should stick with my cannondale r400 for that. I like the idea of trying out cyclocross, since that's what my bike is made for (I know I'll need different tires for that - but I look in the 'cross forum for that).

I've never ridden with fatter 700cc tires, and generally feel like I enjoy the thin tires, and get the perception that these tires are faster than fatter ones. I also have had really good luck as far as flats go with my current road tires.

Questions....

1) Aside from "absorbing road noise" and "superior flat protection" - are there any other real advantages to getting a pair of schwalbe marathons or something similar for commuting - or should I just stick with the skinny tires on my commuter. What do folks think?

2) Also, what specific tires would you recommend (both for a narrower tire (23-25) or a fatter tire (28+). I've been cruising the biketiresdirect site and reading reviews on the tires I see.

3) Is the tire weight really going to be noticeable (in centuries, in commuting, in zipping around town, in 40-70 mile weekend rides) between a narrower road-style tire and a fatter touring-style tire?

4) It seems like all of the group rides I do (not that I do a lot - but might start doing more), everyone has really narrow tires - will I be an alien / be able to keep up with a thicker tire?

Thank you - I feel like any friend I have in REAL LIFE who rides bikes is very focused on their own realm of cycling and can't give me good advice / don't know much about different tires.