Luggage and bags:
A fold up bag is useful to bring presents back.
Clothing/Shoes/Weather Gear: If going out of season consider taking a small umbrella. They are expensive to buy in Spain.
Toiletries and Medical Supplies: Sun protection lotion or buy some as soon as you get here.
Photo Equipment: Camera to upload to VT at the end.
Binoculars to see those views.
Camping/Beach/Outdoor Gear: Mosqito replellent, or the electrical equivalent if you are staying near water or lots of plants are near the accomodation, for your room.
Miscellaneous: If you bring your alarm clock radio with you as I do, and it runs off the mains, don't forget to bring your converter plugs with you as Spanish plug sockets are TWO PIN ROUND !
Voltage is the same as in England BUT where as our voltage is closer to 240v AC, Spanish voltage can go as low as 206v AC, especially at peak demand times. Your appliance will work o.k. but say, a kettle will take longer to boil.
Many people bring their mobile phones with them but DO remember that a call from the UK will cost YOU even to receive the call. If you are going for a long period, consider buying a Spanish mobile phone, two if you are going with company. Then you can keep in touch with each other when at different locations and CHEAPLY.