i wasnt sure where to put this as im quite new to dslr's, but this is sort of a commercial offer of sorts. to make a long story short, a friend of my girfriend owns a modeling agency. we gathered the other night for a pet event and i was brought along to take some pictures. long story short is that her friend presented me with an offer. they need a photographer to fill a certain role (as of yet details are limited so im not 100% sure what that role is yet), and also her son is a professional photographer who has offered his assistance in my learning as well. at this point it sounds more like a freelance position more than an actual steady paying job. im fine with that as i have a 40hr/week (or more) job currently. this would be done on the side as a hobby and a chance to grow, however, i could get paid based on if the pictures i take are purchased. so...i find myself here... my girlfriend has fallen in love with my xsi, and so i gave it to her last night along with the kit lens. since i need to replace my equipment i figured i'd take a deeper plunge into the slr, and order a 50d. i did think about the nikon d300 but that may be overkill (and a bit more than i want to spend just yet) for right now. i also thought about the 40d which everyone praises, but its only $100 less. cameralabs had this to say in comparison between the 40d and 50d to be honest, i will most likely never use the hdmi output so thats useless to me. the 5 extra megapixels is something that i also dont care about yet, but i may soon. if the pictures i take will be going to print i'd want to make sure they turn out (so i can get paid). the interface...well, im only familiar with the interface on my xsi so i'd have to learn the 40d/50d interface anyway. hasnt appeared too much different from the xsi, just more toys to play with. as noise levels are apparently the same, but with the 50d having an increased iso range may give me more latitude as i have no idea where i'd be shooting (when shooting for this lady's agency). although, even on the xsi i've yet to find myself needing greater than 800 even indoors with the kit lens. the vga screen is my biggest catch right now. the screen on the xsi is wonderful, however, there have been times when i've looked at the picture and thought "perfect!" only to get it on my pc and see it out of focus a bit or slightly blurred. the higher resolution screen would, to me, provide more accuracy so i dont have to worry as much between what i see on the lcd and what i will see on my pc once taken home. *takes breath* ok, assuming i dont get flamed too hard for my 50d choice over the 40d.... my dilema is this. lenses. right now, since my girlfriend has taken the kit lens, that leaves an 18-55mm hole in my already limited range as it leaves me with a 50mm as my current portrait lens, and a 75-300mm for my tele. im torn between two L lenses at the moment, and one non-canon. my 50mm and 75-300mm are both cheapy lenses, but im pleased with the results from them thus far. however, both were bought with being replaced at any time, but then again...the 50mm wont be for some time. the 75-300mm is one im looking to replace now. why 'L' lenses? well, as mentioned earlier for the freelance stuff i have no idea where i will be shooting and what the lighting will be like. i also have no idea if flashes will be allowed or not. im looking for something that will give me the flexibility of taking a non-flash indoor low lit shot...and having it turn out. that said, my current choices for filling my 18-55mm gap are: Canon EF 24-70mm f/2.8L USM or Tamron AF 17-50mm F/2.8 XR Di-II LD SP ZL Aspherical (IF) for this, however, im leaning towards the $600 more expensive canon because i figured if i ever did upgrade to a full frame body...the money i spent wont go to waste. i'll be able to re-use it. the tamron is extremely attractive also because it gives me a 17-50mm range, and for only $450. here's where my real problem comes in though. i have no idea if her freelance "job" will ever materialize, and as such i then need to look at what i personally love to shoot and what range i shoot at. my most used lens at the present is my tamron 75-300mm. its captured some absolutely priceless and wonderful puppy pictures while they're in the yard playing. for that i have been considering the Canon EF 70-200mm f/4 L IS USM as a replacement to that. the 2.8 is just too expensive for now. to compound my problem of knowing whether or not the position will work out or not, looking at a bunch of videos and such of "what the professionals carry in their bag" i've notice they all refer to both the 2.8L 24-70, and the 4L 70-200. so obviously at some point i want both regardless, but alas...at the present (and probably for another couple months) i only have money for a single choice. so, after reading this extremely long and boring post (i thank you much if you've made it this far!), assuming no one has any counters to my choice of body....what lens would you get first knowing that it could be a bit of time before you could get the other? go with the one that gives you the range you shoot with the most (but purely for personal pictures), or do you go with the one based on a "job" offer, and one that fills a current gap in your range, but may end up not being used all that much if the job doesnt pan out? i guess another way i can look at the 24-70 also, is that i could use that over my 50mm for portraits (as that seems to be a common use for the 24-70 as well). portraits are something that i do a lot, so in that regard it would get use. i guess also that it all comes down to a simple fact: if im spending $1200 on a lens...it had better get used. lol my apologies for the long post, but i just wanted to provide enough information so that i may get informed replies as to helping in my time of a major dilema. option b is to buy the L that i know would get used the most offhand, the 4L 70-200, and then do the tamron 17-50. that way i have a good 2.8 lens for the freelance stuff, but not too much invested if it doesnt and still be able to fill that gap i missing. im not sure, however, if the tamron can be used on a full frame body...or what the aftermarket is like for trying to sell an off brand lens in the event i go full frame and need to replace the 17-50 (if i hadnt done so before that point). thanks again for reading, and i look forward to hearing opinions on how you'd handle this situation. everything is being ordered through amazon prime so i can get everything here tomorrow, and only 4hrs left to decide...so im in a time crunch!