A decent laptop is now an essential part of your armoury. Never used to be but times change and be glad you’re reading this now and didn’t have to deal with laptops like my Apple 180C ten years ago that had something like 8mb of RAM and found Internet Explorer a struggle… I’m a Mac geek -as are many photog’s and creative’s originally due to the Mac’s superior colour handling ability when it came to print work flows- but these days it doesn’t really matter what you have as long as it’s got a decent processor under the hood. The current MacBook Pro 13-inch would be my choice- it’s tough, good value, rock solid OS and with Photoshop CS4 on board will do all you need.
I know nothing about PC’s at all so can’t really dispense advice on them but as long as its got a fast processor and at least 160gb hard drive then it should be cool.
Software wise Photoshop CS4 is the go to guy. Not cheap but it is industry standard. You can always ‘borrow’ it from work or school if they have a multi machine license. I avoid the camera makers app’s as with Camera Raw/Bridge/PS CS4 does all the organising/raw conversion/post processing I need. I’ve not played with Aperture much but it also seems pretty good and is a lot cheaper.
Storage wise on the road I back up to my old school iPod (60gb, you can enable the ‘use as external hard drive’ option in iTunes) and to a Western Digital Passport 500Gb drive- they are tiny, weigh nothing and power off the USB so no need for another annoying power lead. Double back ups are pretty essential cos if some fecker nicks your laptop you’re done for. When travelling keep the iPod and other external separate as well just in case you lose a bag…
At home I back up to a Western Digital My Studio 1TB drive, these things would have cost hundreds a year or two ago but they are below the £200 mark now and are Mac formatted out the box. They are connectable with Firewire 800 which makes things a hell of a lot quicker (until the new USB standard comes in anyway). I used to back up to DVDs as well but am sorely behind with that… Backing up is essential and you need to be super careful with it. Once gone digi files are gone. Not like you can get your slides drum scanned again. I lost the best days files from the last Mentawai boat trip as I deleted them thinking I’d burnt them to DVD etc already but hadn’t… It was a 3-week trip so there was 20gb’s+ of shots, but it’s still no excuse, it’s only cos I’d sent processed versions of the best shots out to clients that I have copies at all.
Memory card wise get the fastest and best you can afford, it makes a huge difference, the write speeds of top grade cards help clear your buffer quicker so you can shoot more. I use Sandisk's Extreme IV 8Gb. On a 40D I get 600+ shots on the 8gb card which is more than enough for most sessions, indeed I can shoot a whole trip on the one card (unless it’s sequence city with guys like Reubs). One tip with cards- never shoot until they are totally full, when it’s down to the last 10 or 20 change the card out. Things can go a bit odd if you fill the buggers right up…
Always download your cards asap, I'll do a quick edit of dross then back up, twice. So now if you lose your lappy, the card corrupts etc you're still two copies up… Be careful out there.