How can I store my digital photos while shooting weddings? I have two 1Gb compact flash cards, but I don't want to buy more CF cards because I think they'll be collecting dust soon when larger cards come along. What types of laptops or digital wallets are best?
I really think that in this situation, more CF cards is the way to go. You're making money from your gear, so you need to look at the return on investment you'll be getting.
If you take along a laptop or a portable hard drive storage device, you'll need to muck around downloading cards (which takes up valuable time), and you run the risk of messing up your card swapping and accidentally wiping a card you haven't dumped yet. You might even have to pay an assistant to do all this stuff for you.
You don't need to keep your compact flash cards forever to make them a worthwhile purchase. They'll give you 1 or 2 years of faithful service, and then you can sell them on eBay and buy some 8Gb or 16Gb cards to replace them. That might cost you several hundred dollars over a couple of years, but I think it's money well spent. Just think about the benefit of the download/formatting time saved and the reduced risk of losing images.
Hard drives fail. Whether it's your laptop or a digital wallet of some sort, you run the risk of a drive failure wiping out all of the images from a day's shooting. Solid state compact flash cards are less likely to fail, and even if one does fail you only lose a portion of the day's shooting, not the whole thing.
For that reason (hard drives being more prone to failure), I also prefer to stick with solid-state compact flash cards instead of MicroDrives.
If you have a laptop with you at a wedding, you need to think about security, too. Will there be somewhere safe you can leave it? It's going to add weight to your camera bag if you have to carry it around all day. What if it gets stolen? It's much easier to have a wallet full of CF cards that you carry around on your person.
Note that the above is aimed at someone making real money from their camera gear. For this type of photographer, the amount of money involved is miniscule compared to the investment they've probably already made in lenses, bodies, tripods and other gear. The economics are different for amateurs and semi-pros, so you need to weigh up the options for your own situation.