Best choice?

[bigfish50]

Hi everyone, I'm planning a big 5mth trip in a few months (mainly Australia, US & South America) and so I've bought myself a Canon 5D to photograph everything. I still need to build up my kit, but because I'm travelling for so long I want as little kit as possible, without losing my ability to capture both landscapes and people etc. I currently have a canon 50mm f/1.4 as I don't yet have a flash and I needed a lens to let me work in low light, but I need to decide on my main lens. I think the canon 24-105mm f/4L IS USM would cover me for what I want, but what are your thoughts on it? Having read other threads it seems that having a good lens but adding various filters would allow me to capture great images. (It's probably worth mentioning that I love sharpness in an image)

So what do you think - is that the right lens? Also, what flash would be the best? And does anyone know of a great travel tripod? Filters etc?

I'd appreciate any feedback about this as this will be the first time I travel so extensively with a great camera!

Thanks