What makes a city truly great?

Is it the number of museums and libraries?

Or is it the nightlife, including great restaurants and bars?

Perhaps, it's the residents' wealth or those quality-of-life factors, such as residents' income, the unemployment rate, the amount of poverty and the number of crimes.

Probably, it's all of the above. BusinessWeek evaluated 100 of the largest U.S. cities, and using this kind of criteria, San Francisco catapulted into the top spot. It was chosen because it offers a wonderful blend of entertainment, education, safety, clear air and a prosperous economic base.

"As the heart of the Bay Area, San Francisco draws on the prosperity of Silicon Valley and possesses its own diverse history well represented at cultural centers such as the de Young Museum. Residents care fiercely about their cafés and causes; nightlife flourishes in the Mission and the Castro, while tech companies code away in SoMa," writes BusinessWeek.

BusinessWeek's top 10 best places to live in the USA and some fun facts about each one:

1. San Francisco
Population: 808,854
Bars: 394
Restaurants: 3,430
Museums: 70
Libraries: 52
Pro sports teams: 2
Park acres per 1,000 residents: 7
Colleges: 17
Percent with graduate degree: 16
Median household income: $90,640
Percent unemployed: 7.8

2. Seattle
Population: 624,070
Bars: 219
Restaurants: 2,307
Museums: 29
Libraries: 42
Pro sports teams: 4
Park acres per 1,000 residents: 9
Colleges: 8
Percent with graduate degree: 16.8
Median household income: $90,303
Percent unemployed: 7.2

3. Washington, D.C.
Population: 607,731
Bars: 134
Restaurants: 2,066
Museums: 108
Libraries: 88
Pro sports teams: 5
Park acres per 1,000 residents: 12
Colleges: 17
Percent with graduate degree: 19.6
Median household income: $72,110
Percent unemployed: 9.1

4. Boston
Population: 615,462
Bars: 136
Restaurants: 2,064
Museums: 51
Libraries: 54
Pro sports teams: 3
Park acres per 1,000 residents: 8
Colleges: 22
Percent with graduate degree: 13.8
Median household income: $62,180
Percent unemployed: 6.6

5. Portland, Oregon
Population: 598,205
Bars: 313
Restaurants: 2,084
Museums: 20
Libraries: 23
Pro sports teams: 2
Park acres per 1,000 residents: 25
Colleges: 16
Percent with graduate degree: 11.8
Median household income: $65,554
Percent unemployed: 7.9

6. Denver
Population: 597,466
Bars: 207
Restaurants: 1,741
Museums: 33
Libraries: 39
Pro sports teams: 6
Park acres per 1,000 residents: 10
Colleges: 13
Percent with graduate degree: 10.9
Median household income: $59,155
Percent unemployed: 8.9

7. New York City
Population: 8,110,206
Bars: 1,220
Restaurants: 22,320
Museums: 356
Libraries: 341
Pro sports teams: 8
Park acres per 1,000 residents: 5
Colleges: 103
Percent with graduate degree: 9.6
Median household income: $58,608
Percent unemployed: 11

8. Austin
Population: 797,215
Bars: 212
Restaurants: 2,135
Museums: 25
Libraries: 35
Pro sports teams: 0
Park acres per 1,000 residents: 37
Colleges: 9
Percent with graduate degree: 11
Median household income: $65,886
Percent unemployed: 6.3

9. San Diego
Population: 1,319,558
Bars: 189
Restaurants: 3,126
Museums: 53
Libraries: 52
Pro sports teams: 2
Park acres per 1,000 residents: 36
Colleges: 16
Percent with graduate degree: 10.9
Median household income: $79,269
Percent unemployed: 9.2

10. St. Paul
Population: 288,263
Bars: 51
Restaurants: 515
Museums: 19
Libraries: 26
Pro sports teams: 3
Park acres per 1,000 residents: 14
Colleges: 9
Percent with graduate degree: 10.9
Median household income: $60,987
Percent unemployed: 6.3

--From the Editors at Netscape