Easy to google. The blow link should answer your questions concerning metro - bus and others.

http://www.barcelona-tourist-guide.com/en/transport/transport-in-barcelona.html

Re : which area to stay
http://www.barcelona-tourist-guide.com/en/areas/barcelona-barrios-guide.html

I stay usually in Eixample, district north of Ramblas but Bari Gotico (old town) and El Born areas appeal to me as well. Some parts of El Raval area is seedy ( steet girls, potentinally more dangerous.. ) and I tend to avoid for my hotel location. However I hear it's getting sort of popular, especially northern part ?

Also, maribel's guide, very often mentioned on this forum, would give you a whole lot more infos :
http://maribelsguides.com/mg_barcelona.pdf

Agree about Raval. We stayed there in September and although the hotel was OK, (Barcelo), the area is decidedly not OK, especially for females. The area around the Gothic Quarter is much better, yet still very accessible for the Ramblas etc.

Regatrding restaurants, what's your budget? Affordable to one is either too cheap or too expensive to another.

If you want a budget hotel in Barcelona you can look at hostels.com hostelbookers hostelworld and some other hostel sites. In the city centre there are a lot of appartments for rent. This might be nice. Everybody gets there own bedroom and you share a kitchen and the bathroom. Those rooms go for around €50,00 per room per night. I would recomend to stay in the gothic area or aroud Ramblas in The city centre. Easy to reach by metro from the busstation in Barcelona.

Be very careful of pickpockets on the Barcelona Metro. The system is easy to use and other than the pickpocket issue it is safe and convenient.

I use to stay in great value Hostal Orleans (with bathroom, tv, safe, heater, aircondition and 24h desk) in the vibrant El Born district close to everything. Ten minutes to both central Plaza Catalunya, Las Ramblas and the beach. 49€ for a double in December.
http://www.booking.com/hotel/es/hostal-orleans.en.html
http://www.hostalorleans.com/

The area: http://www.barcelona-tourist-guide.com/en/areas/el-born.html

Next door Bar Restaurante Navia is a friendly place serving perfectly fine food at low prices, open almost 24/7. Groups of friends drop by even after midnight for having a huge meal as do many police officers. Can highly recommend Today's soup or stew. I can also recommend l'Aribau in Carrer d'Aribau, 3. On a corner close to the impressive university (from 1450). Here businesspeople and academics drop in for a three course lunch for 8,60€ (before 14, 9,60€ after 14h). Salad or today's soup, grilled meat or fish with poatatoes/vegetables and dessert. I had a wonderful Spaghetti Carbonara the Catalan way (Italians would have died...) for 5,50€ here a couple of weeks ago. Excellent place, and you'll find similar places all around outside the most beaten tourist tracks. http://barcelona.salir.com/laribau

I can also very much recommend the Poble Sec district, the little and very local feel area just between Montjuic and Avenida Paral.lel. Great cafés and restaurants, the best atmosphere and several great theaters close by. http://www.barcelona-tourist-guide.com/en/areas/poble-sec.html
http://www.youtube.com/watch?v=XU3ePGy1_Y0

My budget recommendations
Hostal Centric 5 minutes walk to Plaça Catalunya
http://www.tripadvisor.com/ShowUserReviews-g187497-d208590-r122923903-HOSTAL_CENTRIC-Barcelona_Catalonia.html#CHECK_RATES_CONT

Hotel Pelayo 1*
http://www.tripadvisor.com/Hotel_Review-g187497-d239590-Reviews-Hotel_Pelayo-Barcelona_Catalonia.html
Really almost next to Plaça Cataluna (but no noise problem). This is the least I paid in my recent staies in Barcelona, €25 for a night, single room (yes the bed was for 1 person, bathroom was modern and clean, and rather spacious for a small bed room itself). This is a hotel that occupies one floor of a building. For the price I paid ( €25 in January, 2011), it was quite satisfactory.

I don't think they serve breakfast at Pelayo.

WOW!!!! Thank you so much for all the advice and suggestions. I really do appreciate it and will certainly make use of all of this!

We just returned from 4 nights in Barcelona. It was our second visit and the second time we used habitatapartments.com We had good experiences both times we rented with them. This last trip we had a beautiful apartment on Passeig de Gracia directly across the street from Casa Batllo. It had a balcony with an impressive view.

The metro is very easy to use and inexpensive. Buy a T10 ticket. You can very easily buy tickets at machines in the metro. We had no problems with nor saw any problems with pickpocketing, although I am always very careful and I know other people have reported problems. We went to the big Estacio flea market and kept our belonging close to us, but had no problems there either. We used the bus to get from our apartment to Parc Guell and although it was crowded enjoyed the sights along the way.

We love to eat tapas and drink cava at Ciudad Condal and Cerveseria Catalana (?) both in the Eixample. We also enjoyed buying food and having picnics in the beautiful parks of Barcelona, although you may not be able to do that in December.

Enjoy your trip. I look forward to going back and experiencing more of Barcelona.

I second opaldog's recommendation of Cerverseria Catalana. I think it's on Mallorca Street in Eixample. Delicious food & reasonable prices.

We stayed at Hotel Gran Via in Eixample. Prices were reasonable & room was quite large, in a great location, close to Casa Battlo & Casa Mila. However, we had one bad experience. We arrived early in Barcelona, so our room wasn't ready when we arrived. We left our luggage at the front desk, & went sightseeing. When we returned, we discovered that our backpack was stolen. After many conversations with the hotel, they agreed to not charge us for our room.

Hello. I will be staying in barcelona Hostal la Palmera. Any suggestions for this hostal ?
Thanks

Shahryar

Hostal la Palmera gets reasonably good reviews: http://www.booking.com/hotel/es/hostal-la-palmera.en.html?aid=311984;label=hostal-la-palmera-9fLnGIyeu32xmPRxX*1M6wS17636259913:pl:ta:p1:p2:ac:ap1t1:neg;ws=&gclid=CJ-3yr7X37MCFTJ2cAodiWAAdQ

And it's next door to probably the finest food market in the world, La Boquería:
http://www.boqueria.info/index.php?lang=en

Two hundred meters from the oldest restaurant in town and the second oldest in Spain, Can Culleretes from 1786. Traditional Catalan food at reasonable prices and the best atmosphere. Also popular with locals. Had once again a great meal here about a month ago.
http://www.culleretes.com/
http://11870.com/pro/can-culleretes