There are many good makes to choose from, but shapes and sizes tend to vary between manufacturers. Popular choices include Giro, Bell, Met, Specialized...
As a minimum, make sure that any helmet that you buy meets the appropriate CE safety certification.
Go and try plenty on, and find one that suits the shape of your head. Some people have narrower, more oval heads, some people have more circular heads, some people are somewhere in-between. Personally, I get on well with Met helmets, but not Specialized ones.
Take time to adjust all the straps correctly and make sure that it is sitting properly on your head. A good bike shop should be able to take time and care to give you the right advice and make sure your new helmet is correctly fitted. Whereabouts do you live? Folk on here might be able to recommend a good shop local to you.