Whats in a name?

Yes, if it's amazingly bad and the same as 5 other novels it might reflect bad on you, but if you stick a bit of imagination in it, you'll be okay.

One of the agent blogs I read regularly has mentioned that titles can be changed, but a manuscript that has a cliched or overused title makes them wonder if the author has any clue about their market.

Yes, titles can be (and often are) changed before publication. However, there are enough strikes against an unpubbed author, so you always want to put your best foot forward.

My gut feeling is that it doesn't matter a hill of beans.

If you're unsure that calling the ms 'Murder and Rapine on the Ferris Wheel' is such a good idea,
call it 'Working Title: Murder and Rapine on the Ferris Wheel'
when you send it to the agent.

The name may make a difference sometimes, although it's probably small. Remember, it is the writing and the story the agent is going to look at, so get that right and the name won't mean the slightest little thing. The agent, if they take you on, may suggest a name change, and the publisher may also suggest a name change which is different to both yours and the agents. Although it doesn't hurt to have a snappy title for your novel .