can you recommend a bike for a 10 mile commute?

Get a touring bike. It's like a road bike, but it's built for long distance, heavily laden riding with more concern for rider comfort than speed (relaxed geometry) and for durability over light weight.

Hybrid/city bikes are road versions of mountain bikes and neither, IMHO, is the best for commuting. The upright posture and flat handlebars are not as good aerodynamically and are tougher on your back and butt. Try rolling down a long downhill on an MTB and you'll see: you'll want those dropped handlebars.

Furthermore MTB's are overbuilt and too heavy to be optimal for long commuting. They handle potholes and curbs better, true, but a commuter is looking to avoid them not survive contact. Tourers are not as light as racers, but you still want your bike to be as light as possible. Try climbing on an MTB vs a tourer.

Cannondale and Bianchi make good touring bikes, but you'll probably need to find a used one for $500. Good luck!

I agree with the touring option as the best choice. A MTB or converted mountain bike will not yield by far the benefits of a tourer.

In any case a Hybrid could be second best option and a good one too. Not as heavy as a MTB and stronger more durable and comfortable than a racer.

At any rate, check the frame well. Look for it to have holes and preparations to put in crud guards and a rack for panniers, also rear and forward lighting! This "extras" are often overlooked and you will soon find out they are a necessity and make a world of a difference as far as comfort, and safety are concern!

Not many MTB or Hybrid will allow for this extras, so ask around, shop around, and if possible, buy the bike with these "extras" or al least make sure you will be able to place them without a problem in the future.

Some day you will have to take along a jacket, maybe rain garment, lunch, etc.? Do not forget these items.

A second hand bike with these qualities could be very attractive for the money and will work as good as a new one, so consider this option too.

Finally, make sure the bike is the right size for you. Try getting it sized for you at the shop. A good bike store is your best option.

Get a hardtail mountain bike. If you can find one, get it without a front suspension as well. You don't need that weight or complexity on the street. Eventually replace the tires with 26x1.5 slicks that have a max pressure of at least 80 psi. The bike will be much better on the road that way. A $500 hardtail should get you a pretty good bike with reasonable weight.

Hybrid bikes are also a possibility, but I think you'll get more bike for your money with the hardtail MTB.

HTH

Take just about any road bike or converted mountain bike (slap some street tires on that bad boy) and you are good to go.

10 miles is actually not as far as it sounds!

I ride 8 miles in and 8 miles out each day on an old converted mountain bike with street tires. It's the perfect all weather commuter.

Drop... um... $60.00 (American) on a tune up and whatnot for your current ride at the bike shop and you should be good to go.

http://www.evanscycles.com/product.jsp?style=87634

or look at a Scott road or mountain bike. I would go for hard tail you don't need the weight of full suspension. Have you looked at the ride to work scheme? Some employers will help pay for a bike for you to cycle to work which could put up your price range.http://www.dft.gov.uk/pgr/sustainable/cycling/cycl...

Trek Madone should do it.

EDIT, uh 250 pounds is about $125 US ? Lots of luck on that one. Not going to happen.