In reply to Brian Pollock:
Well for UK trad 50 metres is enough, but Scottish winter 60 metres can speed the day up, quite often the best way of climbing a route has belays a bit more than 50 metres apart OR you'd end up doing some very short pitches in paranoia of running out of rope. Euroice 60 metres is more important again as the bolted belays can be more than 50 metres apart.
For Scottish winter 8mm is great as it lowers the weight of a 60 metre rope for walking in, for euroice it's less important IMO as you are not walking in very far with the rope although a heavy rope may weight down on you towards the top of the pitches. A 60 metre half rope is also usefull for short single pitch routes (
0 metres) as the second can tie in to the middle and the leader to both ends.
The downsides to 8mm are less security as a single line for alpine use (and for two seconds), supposedly quicker wear (not what I've found with my mammut pheonix) and they won't work as well in standard belay devices as high factor falls can be hard to hold.
In your shoes I'd probably get a 60 metre 8.2mm to 8.5mm dry treated half rope (although you could consider a 8mm). I see little advantage to getting a mutli-purpose rope seeing as you already have a single rope and anything more than 8.5mm is getting a bit heavy IMO.
