Do you need a 5D?? its a great work horse, and it'll produce wonderfull results but only if you know what you're doing, but the 40D is at least as good if not better in usability.. its well set out and has some great functions on it.. some not found on the slightly dated 5D..
I think you'd be very happy with the 40D and its cheaper too.. iv got both atm and love them both for different reasons.. They both have a smashing feel to them, very solid, but dont forget that the 40 also has some weather sealing that the 5D has'nt.. i need to get out and take some picture with these cameras and really see what they have to offer as iv only had them a week or so, Iv just upgraded from the 400D, even with the 40D it is an UPGRADE!!!.. you wouldnt be dissapointed.. this is only my opinion and im not the most experienced but i know what i like..