I've stayed in a few hostels when in the US and Asia.

As mentioned earlier, Hostelling International seem to have decent standards and are less party like and have more people of different ages ranges (so you're not stuck with a load of 18yo backpackers if you're say in your 30s - although not always a bad thing if some rather nice girls!). That said, I've seen bottles of alcohol in their fridges when there's a no alcohol policy.
Occasionally you get someone who bangs about a bit when returning / coming into the room at 3am, but as with most shared places, ear plugs are an essential thing what with a practically guaranteed snorer if there are more than 2 in a room and street noise.

Some hostels are dives and I'll pay a premium to avoid them. Others rather nice especially when you're paying $40/night compared to 3-6x that for a hotel that might be in a worse location.
Then again, I've seen private rooms in hostels going for higher prices than fairly decent hotels in the same area. i.e. San Francisco recently - $129 in a hostel, <$100 in an IHG hotel.

I like staying at the hostel near Tufts Medical Centre in Boston (especially if I arrive at say 8pm and want to pick up a rental car at 9am, or fly somewhere). $45ish a night, basic free breakfast; good kitchen; bathrooms out of the room; clean and quiet; couple of blocks from Boston Common / Chinatown / Shops; 10 min walk to South Station; Red / orange line metro 150m away etc.
Usually a good $250+ for the airport Hilton so I'll get the free silver line bus to South station and stay at the HI hostel near Tufts. Great for an early run as well.

I sometimes stay in a couple of places in New York as a couple of nights in a hotel can easily hit $500 compared to a 1/5th of that in a hostel.

Places like Miami have a lot of party hostels near South Beach so might want to avoid them if you want peace and quiet.

Depends who you're traveling with as well. If I was with a girlfriend and a hotel cost $120 compared to $40-50 each in a hostel, the hotel would win out. Perhaps the same with a male friend if we could get a room with 2 beds.
Sometimes I just want my own space and the extra cost is worth it.

Just check out comments on hostelworld and tripadvisor.
Quite often they'll mention that the hostel is geared towards partying, drinking etc. A bar onsite usually means that very thing.
Hostelling International and Apple Hostels (Philly etc.) are generally good bets for a lot less drunken behaviour. They do nights out / bar crawls / clubbing nights but generally just at the weekend.
Certain locations are geared up for partygoers as well. i.e. Goa more so than say Hong Kong or Singapore.