A fee free online savings account like ING for sure! I think you need to see the amount being saved as a seperate sum so its concrete and real.

On pay day I pay off all our bills for the fortnight and allocate some spending money to have available to withdraw as cash then I transfer the remainder to our savings. It becomes a challenge to see if next fortnight we can have our expenses down so I have more left over to add to savings. I get a boost from hitting new milestones with the savings- watching it creep to a new record is exciting and motivates me to save. I feel more excited by seeing the savings hit a new level than I do by realising we spent more than usual that fortnight and have less to save.