[RexK_Cozumel]

Yes you should probably save up your money for now. The 5D is probably the best camera for your purposes but it is a very expensive camera. For now I would invest in a couple flash guns and light stands. I say this because you are going to be doing mainly location shooting and this is a very portable lighting setup. Next thing you will want to do is get the glass. Keep in mind that you will eventually want to go with a full frame camera so make sure that the lenses that you get are compatable with a full frame camera. I am not too familiar with canon lenses so I can not suggest lenses for you but I know that the crop body lenses are not compatable with full frame sensors like nikon lenses are. (although you lose a good portion of the resolution at least you can still use the lens) Anyways like I said for now I would go with getting the lighting setup that you will need. Canon has some good flashes but honestly the Nikon lighting system is a lot better IMHO. If you are using off camera flashes (which you will want to do) and are not using TTL then you can use nikon flash guns with wireless triggers. This means however that you will need to manually adjust the output of the flashes (not a big deal once you get the hang of it.) Anyways have a loook at the strobist website for more info on off camera flash.

Also what about canon makes you want to go with that system? I mean other than the fact that your father in law has a canon. Have you used any of the other camera systems out there? If not you really should try out the other systems as well. The feel of the camera is very important. I would not limit myself to a system just because I know someone that has that system unless they have a lot of high quality glass that I could use. But honestly the lenses that your father in law has is not really good enough for professional image quality aside from the 50mm f1.4 (I am pretty sure that canon does not make a 50 f2.4 but I am not positive on that)