I would take 600D, it is liter than the 60D (so you can take it into the trip or during the walk and add some lenses), cheaper and has nearly the same functionality.
Never worked with xxD (but made a few shots with 50D) - if I pay more, it'll be a full-frame camera, so cannot comment on 60D much.
Made 64 000 pix with 400D, around 45 000 with 500D and below 10 000 with 600D now, mainly portraits, sometimes in clubs, rarely do video. 600D has much-much longer battery life, than 500D, especially for video / live-view. Buy the extra 2 ACME power batteries for ~17$ each, which are lite enough, and you can shoot and do video for 2 days.
All in all, I'd recommend 600D as a first camera, and then you'll see what you're missing. Although I think it's a very nice start for the first 2 years.