what relay?

I want to use arduiono to turn my room lights ON/OFF and I am confused on the type to use..i live in europe so I use 220V..should i use a normal relay or a solid state one...? can you propose something please?

should i use a normal relay or a solid state one

It is up to you. Solid state relays are silent but expensive, they don't actually turn the thing off as there is still a very small leakage current going through so it can give you a shock when you think it is off.

Mechanical ones give true isolation and are cheaper, but are noisy and less reliable. It is the contacts that should be rated for 240V AC at at least twice the current you want (applies to solid state as well). The coil can be 5V but is normally 12V.

As you don't state the current I can't recommend one but look here:- http://uk.farnell.com/jsp/search/browse.jsp?N=500006+1001698&Ntk=gensearch_001&Ntt=Solid+state+relay&Ntx=mode+matchallpartial