My business partner votes Lib Dem and he wants a change to PR regardless of who wins as he feels it more democratic.
Whilst I can see the democratic value of PR, as mentioned previously, it would have the result of a hung parliament, which I don't believe would be the best thing for the country
I think a reform of the HoL including a different system of representation would be a good way to go. You have one house representing local issues and one representing national.
You would of course have to trim the number of MP's in each house - at least so they can all sit down at once.
Maybe retaining a few appointed life-posts in the HoL which are only replenished upon the death of a previous seat holder might keep some balance with the work the lords currently do.
I think any LibDem would have to change the voting system once elected - although I suppose the values of FPTP would shine through once you're in power.
I would change the voting system, but only with full-scale reform of the houses.