Best thing is to go to a large carpet store & look around, asking questions & checking out prices. Read up on different types of fibers & treatments that prevent/minimize stains. Carpeting is rated on how heavy the traffic/wear it can take, and the prices usually correlate to that.

Would you entertain the idea of cork flooring? It has all the qualities of carpet without any of the allergy/dust issues. It is one of the world's best insulators (keeps you warm in winter and cool in summer) and is a fantastic sound reducer. It can be made water resistant or water proof. It can be permanent (glue down) or semi permanent (floating floor). It can "mimic" everything from hardwood, to sand, to marble. Granite and slate finishes are very easy to produce.

It ranges in colour from "almost" pristine white right through to the darkest blacks. Reds, blues and any shade of brown are easily found.

Cork comes in two different installation options. Glue down cork tiles are permanent and are water proof. Perfect for bathrooms, entrance ways and kitchens. They are known to last 70-100+ years. The install is expensive but worth it.

A floating floor is a semi-permanent floor (can be taken out easily) that can be made water resistant. Perfect for every space BUT NOT a bathroom. Installation is the same as a laminate floor and the floors can last upwards of 25-30 years.

Prices are comparable to medium end carpet+low end underlay. At least the prices at icorkfloor.com and corkfloorsales.com are comparable. Other retailers believe this to be a specialty floor that requires specialty pricing!

Just an idea.

Most people want soft and warm on bedroom floors. There are lots of choices that resist stains, and upper floors generally do not get dirty as easily as main floors. I used commercial carpet in my dining room when my children were small, as we used the room daily. It wore like iron! I could scrub it with soap and water on a facecloth, and it stayed perfect. Go play in the carpet store. I'm sure you'll find the perfect product for you.

Are you carpeting the stairs leading up to the second floor? If so, I would use a lower profile carpet on the stairs. Longer carpet on stairs tends to look matted down and worn faster. I like frieze for bedrooms.