I did about a 500ish mile trip a few years back. dedicated a day to picking up everything I needed for my homecinema speaker setup. made like a saucepan shape from wales across lower england
It's wasn't all in one go (thank god) but broken up into several legs.
swansea>cardiff (went to richer sounds but they were lacking
)
cardiff>bristol (went to another richer sounds, bought the amp, cables and center speaker)
bristol>dorchester (visiting clan mate to purchase two KEF speakers/monitors as my rears, bought for a bottle of whiskey and port
)
dorchester>portsmouth (picking up some front speakers off a forums member for £20 xD )
portsmouth>swansea (the journey home of one very tired sasso)
to be fair I really enjoyed it as it was quite nicely broken up with time to have a little chill at the first few stops. some easy motorway to start off, then dual carrigeways, then single lane country roads, then working back up to motorway pretty much all the way home... good to just floor it and get back with ma goodies
carrying it up the stairs wasn't fun though