What's it like to live in San Diego?

If you don't have a car, can you live close to downtown and use public transit? What's the best neighborhood close to downtown for young professionals? What's the average rent for a large studio or 1 bedroom? What are the major companies with offices in downtown San Diego?

I had stayed in San Diego last year x 2 months. I bought 2 maps before going to San Diego. However, unlike San Francisco which you can explore on your own just with the map. San Diego is different. I found that both maps where incomplete. I bought a 3rd more complete one but too small to be seen by the naked eye. You need a magnifying lens. What's the reason for this? San Diego is so widespread.
I had only appreciated San Diego when I explored it by riding the trolleys. There are bus stations in most trolley stations. Some places are accessible by buses and trolleys while others are not.
Unlike San Francisco in which you can really survive without having a car. Muni Buses are too accessible! There is also a BART, which is the Bay Area Rapid Transportation. I had been to LA from San Diego by riding the Greyhound and the Amtrak. There are areas downtown in which you will survive in San Diego without a car.

Best Neighborhood close to downtown for young professionals:
It will depend on where you will work. National City is accessible to buses and trolleys. A 2 bedroom room usually cost $700 in the area across Paradise Valley Hospital.
It is more expensive in the area of UC San Diego. A studio type will cost more than $1,000.00.

MAJOR COMPANIES with offices in downtown San Diego:
I had been to Greyhound and Amtrak offices in downtown San Diego. I didnt notice other companies there. These are the only times I went downtown to get a ride going to LA.

Everything you need is right here:

http://www.sandiego.gov/

Downtown San Diego has changed. With the development of the Padres Stadium "Petco Park" - Downtown living has become more about lofts and high rises. The cable cars run through Downtown. Most of the action is in the Gaslamp District.

Major employment opportunities are in health care (lots of medical centers), hospitality (hotels and travel) and even in broadcasting (as NBC is Downtown). But there is much to do in San Diego and your opportunities are not just limited to that.

Downtown, the nightlife is great for young professionals. Lots of great restaurants and bars. However, don't discount the beach cities like Encinitas or Del Mar. You can find some good apartment rentals, but you have to look online and in the paper and be on top of it, as housing goes fast.

Mission Valley is developing more - (it's the central area where lots of apartments are now going up) and there is everything you need there for practical suburban living (shopping, theatres, restaurants, etc.)

It all depends on what you like and what suits you.

Life in SD is friggin great. Here's a few tips. Downtown is cool. But look into Pacific Beach. Really cool place...lots of twenty and thirty somethings and right next to the ocean and Mission Bay. Can be kinda young...alot of SD university kids live here. It's a 10 min drive to downtown.

Living in San Diego without a car is pretty hard. If you lived near downtown and worked in it, you could use public transit, but the whole system is not great.

I believe it is possible to live in San Diego without a car if you get yourself perfectly situated, but it's going to be very difficult to do so.

As to the other questions, best to just come down here and hang around the gaslamp district coffee shops/bars and ask/talk to the locals.