Rutt and Tuke said:
Obi-wan, what do you think of olefin? And do you have any preferred brands? (you can pm me if you don't think it appropriate to post).
Olefin or polypropylene (the terms are interchangeable) is used a lot in making berber and commercial carpeting. On the plus side, the solution dye process makes it very stain- and fade-resistant. Nylon and polyesters usually just go through a surface dye process, but this doesn't diminish their stain- or fade-resistance.
On the minus side, olefin can be a very rough fiber (see Virgo10's and battricia's comments). I have seen some rough nylons and some soft olefins, but overall olefin tends to be rougher.
Another thing about nylon vs. polyester. Nylon tends to be more expensive due to the petroleum-based raw materials used in manufacturing, but like I said it's the best man-made fiber in carpeting. If you get a polyester, make sure it's a PET polyester. It's stronger than standard polyester (almost on par with nylon) and also it's made out of recycled plastic drink containers. This helps make it a less expensive alternative to nylon.
WishinOnaStar, it sounds like you might have a frieze. It's a cut pile with a really tight twist to the yarn and is sometimes called a California berber. I joke that "frieze" is French for "shag".

Friezes usually have high performance ratings and are very good for family rooms.
I've also heard the same complaint that mrsv98 had about steam cleaning berber. The loops tend to hold the moisture better than a cut pile so it takes a little more time and effort to fully extract.
As for brands -- I won't say who I worked for, but Shaw, Mohawk, and Beaulieu are the three largest manufacturers in the US. You should find all three available through most retailers, and all three are good strong reputable companies.
One last comment -- definitely go for a good pad (at least 6 lb for cut pile or 7.5 for berber), and I'd definitely recommend a pad with a moisture barrier if you have pets. That way accidents that might penetrate to the pad won't get trapped in the pad.
Okay, I probably gave you more info than you needed. I'll be quiet now.
