Appliances, Electronics and Hardware stores
Prices of appliances and other heavy-duty goods like power tools are average in Spain when compared to other EU countries, so buying them when you arrive will save you the hassles of buying endless plug converters (a fire risk when there are too many in your house at once). It will also avoid the odd differences that can make your life difficult. For instance, if you are shipping a washing machine from either the US or the UK, you are condemning yourself to forever washing in cold water. Spanish washing machines heat the water internally after loading up with cold water only. As a result, no laundry room is ever equipped with a hot-water tap. You see the problem.
Smaller appliances are fine to bring (and will probably work out to be easier for you anyway as locally made small appliances are often unreliable and a bit funny-looking) as long as they run on 220V. Double-check this, otherwise you run the risk of literally blowing out your appliance(s).
Establiments Miró, S.L.
http://www.miro.es/tiendas/index.php
This is the place to go if you want a comprehensive selection of electronics at the best price. A national chain, Miró, has about 15 stores alone in Barcelona. They post their latest promotions on-line and have an excellent exchange policy.
El Corte Inglés
http://www.elcorteingles.es/
The biggest Spanish chain has a variety of appliances, electronics and hardware for your new home. Due its one-stop shopping factor (clothes, cosmetics, groceries, etc) locals often include their household appliance shopping needs in the same trip to their neighborhood El Corte Inglés. They can overprice their items, though, so it’s worth spending the time and effort to look around first.
Caprabo
Aside from a wide range of groceries, the supermarket sells household goods and audio-visual equipment. The quality is not all that high, but if you are looking for an inexpensive TV or hairdryer that will need replacing in a year, a supermarket like Caprabo is a great option.
Conforama
A great, low-price store for all kinds of furnishing and appliances.
http://www.conforama.es/
Loquo
http://www.loquo.com/ce/for-sale/furniture-appliance/405
Second-hand items. Worth a look if you are not staying forever or would like to grab a bargain. The usual cautions about buying privately apply though – be cautious and be prepared to get the fridge home in your own car.
Servei Estacio
http://www.serveiestacio.com/
This six story building houses one of the most comprehensive home and garden stores in Barcelona, that carries a limited selection of electronic needs, as well as all the items you need for home repairs and gardening. Servei Estacio is centrally located in Eixample and is constantly featuring a number of in-store promotions.