I do my 4 mile commute in khakis or even stiffer pants...stupid "professional dress"....the worst thing that happens is the backpack sweats, I really should get a messenger bag or something.

I usually commute in my work pants (Dickies 874 traditional work pants). I find the Dickies to be more comfortable than jeans due to the smaller/flatter seams. My longest commute in work clothing so far has been a 26 mile or so round trip with hills. If I have a clean pair of work pants and a clean pair of jeans and I'm going out to run an errand I'll always grab the Dickies. However if it's just a short trip the jeans are usually fine. Are you required to wear jeans for your commute or just don't want to try out other types of pants?

I spent last winter riding my mountain bike 10-15 miles each way in jeans. It worked but was uncomfortable. For some reason when I took my FG out I wore my roadie gear. Much nicer.

I commuted all thru college about 5mi each way wearing regular clothes and shoes and carrying a backpack. It worked OK. If the weather was really bad I took public transport or caught a ride with a friend.

jeans are fine, but i recommend you get a strap for your ankle to keep your pants away from the gears/chain

i highly recommend the rack, wearing a backpack sucks imo

If you are riding a FG getting your jeans caught in your chain can be..... interesting.

Backpack + jeans should be fine as long as you don't work yourself up into a lather on the ride. Backpack is fine too. I ride with one 29 miles round trip most days.

I commute 5 miles each way to work. A couple of short 10 % grade hills, but otherwise mostly flat. I wear Jeans, t-shirt and light rain jacket. Jacket is not cycling specific, just there for some wind protection since can get a bit cool in evenings and might rain. Jeans work fine. T-shirt is a bit soaked so i keep a fresh one in the backpack. Have been wearing nothing but normal clothes (jeans/t-shirts) commuting under 5 miles for last 4.5 years. Always have backpack with me too. Never been a problem, you'll be fine.

I ride in street clothes during my short 1 mile commute to work. I also wear a messenger bag to carry my laptop and a change of street shoes. I ride conservatively (read:slow) as to not work up a sweat during warm days. If I had to commute further than say, 10 miles, I'd probably wear cycling gear and carry a change of work clothes in a pannier.

Jeans and a t-shirt work great for me. I switched to a bag on my rack two weeks ago, and am wishing I'd done it sooner. I never had much in my bag, but the weight off the shoulders is wonderful.

I used to tuck my right pant leg into my sock, but then I got a bike with a fully enclosed chain guard.

I'm going 4 miles each way. If it rains I change at the office.

You will be fine man! I wear basic cloths (shorts, t-shirt, jeans.. whatever) on my commute of 13.5 each way. I just recently ditched the backpack, I prefer the rack/panniers but the backpack worked just fine!