I've done the dump to laptop thing, and juggled multiple small cards too. My advice is to
buy the biggest card(s) that you can afford, that work in your recorder and are somewhere near the price/size sweet spot. Not having to worry about transferring, laptops, power for laptops & transfers, etc is worth the expenditure.. especially in a festival atmosphere when there is never enough time for everything. 8 gig or larger cards are important (vs many small 1, 2 or even 4 gig cards)
because they can hold more music for the same storage space. You maximize total usage. If you are using 2 gig cards, running 24/48 for example and record a one hour set you've used half the card.. then what if the next act's encore goes over the hour mark? You'll end up with lots of cards that are only partly full. keeping track of how much space is left on which card is a PITA. Big cards = piece of mind.
I recently bought a Transcend 16gig SDHC card bundled with USB card reader a couple months ago for $90. Works perfect in the R-09. At the time I considered nothing less than 8gigs minimum, now I'd buy no less than 16. I was running two rigs and still juggling cards after I filled the 16 gigger, should have bought 2 of 'em. Now I'll wait until my next big fest (likely early fall) and buy even cheaper. I'll get nothing less than another 16, maybe a 32gig by then. No swapping all weekend.

Transfer when you get home and enjoy the fest while you're there.