There are few places more exciting than the pulsing downtown of a big city. There is a vitality and diversity that is palpable. Sure, it might be kind of noisy and dirty and crowded. But there is so much going on � commerce, entertainment, education, travel, socializing � that it's easy to overlook the grime and congestion.

At the same time, there are few places more depressing than the forgotten downtown of a struggling big city. Those downtowns have the dirt, but the noise and crowds are gone. In their wake is crime, poverty, and the only thing that's palpable is a sense of hopelessness.

Of course, things are not black and white. Downtown in City A is not ideal in every way and without problems, while City B's downtown is totally pathetic and beyond salvage. Manhattan may be the center of the world, but it has problems, starting with a lack of decent housing that's affordable on working class wages. Downtown Cleveland may be literally the poster child for a burned-out, abandoned central city. Yet there is new investment, including sparkling sports venues and a smattering of new housing.

Determining the "best" downtowns is, of course, entirely subjective. Sure, you could count the number of jobs or museums or nightclubs with live music. But simply selecting the quantifier is a subjective exercise. Determining the "best" downtown is more of a seat-of-the-pants exercise. What does it feel like to be there?

Within most states, there is little competition among big city downtowns because most states have only one or two big cities. California has no fewer than 11 cities of at least 300,000 people. (From north to south: Sacramento, Oakland, San Francisco, San Jose, Fresno, Bakersfield, Los Angeles, Long Beach, Anaheim, Santa Ana and San Diego.) Some of these are world-class cities with dynamic downtowns. Some of these are the butts of many jokes. Some are both.

Here then is the California Planning & Development Report ranking of the best and worst.

Best Big-City (300,000-plus) Downtown in California:

1. San Francisco. A recent story in the Economist magazine, which was not altogether flattering of The City By The Bay, said, "San Francisco is, indeed, one of America's most alluring and urbane spots. Next to it, every other big city in California resembles a glorified suburb."

One of the issues, however, is identifying San Francisco's "downtown." The Financial District is the core of downtown, but that's mostly a gigantic employment center. We also view Chinatown, SoMa, Nob Hill, the Tenderloin and the Civic Center as part of downtown. When you consider this larger area, it's hard to identify what could possibly be lacking � except maybe the aforementioned decent affordable housing. There are a wide variety of jobs, first-rate museums, maybe the best live theater west of New York City, world-class restaurants, popular public gather spaces, varied architecture, shopping, a scenic waterfront, public institutions and great transit. There is even a baseball stadium and growing UC campus nearby.

1. (TIE) San Diego. It probably looks like we chickened out, but we really can't decide which is better. Twenty years ago, San Diego wouldn't have been a contender. But since then it has become a downtown of unusual grace and sophistication. Beginning in the 1980s with the Horton Plaza shopping mall � admittedly a bit garish � downtown San Diego has turned into exactly the kind of lively 24/7 location planners always dream of. Horton Plaza kick-started the revitalization of the adjacent Gaslamp district, an historic area that is now home to the city's nightlife. The Gaslamp, in turn, spawned a huge construction boom in high-rise condos. There's the requisite baseball park, of course, but best of all San Diego had the first � and still the best � urban Ralphs' market anywhere.

3. Long Beach. For decades, downtown Long Beach was simply a place with potential. Many of the city's aggressive redevelopment efforts either backfired or didn't fire at all. A long-struggling, enclosed shopping mall was a cancer. A no-man's-land of vacant lots cut off downtown from the waterfront. But much of this has started to change in recent years. The mall is gone. Ethnic restaurants and shops are everywhere, often underneath new loft residences. Entertainment venues have filled in the no-man's-land and now connect downtown hotels, shops, offices and eateries with a great waterfront. There may be no West Coast downtown that is a more enjoyable place to be a pedestrian.

4. Los Angeles. Yes, downtown L.A. has been on the comeback for, oh, 50 years. It's still very much a work in progress and it's not necessarily an inviting place after hours. But while the redevelopment work continues, a lively, incredibly international community has taken over much of downtown. A walk down Broadway will have you in Korea one minute and El Salvador the next. Downtown L.A. has great restaurants and watering holes, the new Disney concert hall, the most remarkable cathedral built in America in many years, Staples Center, both classic and cutting edge architecture, and even new housing.

Worst Big-City Downtown in California:

Fresno. It's really not even close. Bakersfield, Oakland and Anaheim all have less-than-ideal downtowns, but none of those districts is as desperate, depressing and even threatening as downtown Fresno. The hideous 1970s office buildings are the least of the problems in Fresno's core. The place is one gigantic real estate "opportunity," and it's usually deserted after 6 o'clock. Yes, there is a nice new minor league baseball stadium, but that's about the only reason locals willingly go downtown.