If you’re going to vote for a major party, vote Lib Dem. Michael Howard is a vile demagogue, and the Labour Party don’t belive in the rule of law. No matter how objectionable you find the Lib Dems, voting for them is the only non-morally-disgusting major party vote (and if you support a non-major party, a Lib Dem vote is the only way you stand the slightest chance of getting a fairer electoral system and allowing them into the system).
Otherwise, it doesn’t really matter, does it? Nobody’s going to take spoiled ballot papers seriously, and nobody’s going to take votes for the assorted Silly Parties seriously until we do have PR. So, whatever. Vote for Tarquin Buckethead, stay at home, or write "Tony Blair is a knobber" on your ballot paper; it doesn’t make any difference.