For 2010 (and until they change their minds again), qualifying is low fuel again. The tyres that the top 10 cars (which make their way into the Q3 section of qualifying) qualify on are the tyres that they must start the race on.
There is no refuelling this year so they will start with full fuel cells (which are now in the region of 35% larger than last year, though they rarely filled them up last year). The drivers are complaining that the tyres are going off in a big hurry as a result too.
One other thing, like last year, there are two compounds of tyres every weekend and each driver must use both compounds during the race. They can qualify on soft tyres but have to deal with a heavy car (in the region of 20% heavier than the minimum weight) on the less durable tyre or qualify on the hard tyres to have a better chance of lasting a bit further into the race before they have to stop for new tyres. Red Bull have managed to change tyres in less than 2 seconds during pre-season testing