My favourite is Filipes Kifsgate - a huge rambler with white multi-headed flowers. It will cover your wall in a couple of years and be a real stunner when it gets into it's stride.

I have just planted Rosa 'Excelsa' it is a vigorous climbing, deciduous rose which reaches 10ft. It has scarlet flowers in late spring and summer.
Why not look on Goypeadia members have posted their photos of climbing roses.

Please take into consideration that most ramblers flower only once in a season whereas climbers can flower continuously. Ramblers also tend to flower in clumps but climbers will flower all over. You wil also have to keep cutting out old stems, bringing the new pliable stems down and tying them in, otherwise all the flowers will grow at the very top of the stems. May I suggest an excellent climber 'Compassion' a pink and yellow variety.