the main difference between the two is the size. by the time the two look comparable in "definition" you will be sitting far enough back that it might be uncomfortable to read text on the tv (and from personal experience text is always harder to read on tvs than on monitors for some reason). also at that distance the size difference between the tv and monitors is negligible (due to perspective).
for that reason alone the smaller monitor would be a better choice.
i work in the computer aided drafting and design (cad or cadd) field which does alot of 3d modeling and i can tell you that you definitely want a monitor that is capable of delivering a decent pixels per inch (ppi). a higher ppi will make it much easier for the end-user to get their work done. also, two monitors (or one large monitor such as the expensive and monstrous u2711, a bit more common in graphic design though) are pretty much a standards in the fields.
the reason for this is because when you are 3d modeling (again ,depending on actual situation and programs used) you normally have many different viewports (windows) open to allow the end user to visualize what they are modeling. all these viewports take up screen real estate (space) so the more you have the easier it is to work. one screen can feel cramped, two seems to work out very nicely, three is a little too much to handle but once used to it can be useful, dont go more than 3, two is ideal.
if i were to make a suggestion you should get two 1920x1200 monitors around 22" in size. if these are out of your budget at the very minimum 1920x1080 resolution. personally i'd go with ccfl backlighting (models without an "led" tag on them however led backlit monitors would work also. if you are doing any sort of rendering where you need colors to be very accurate you will want to look at p-ips, h-ips or s-ips monitors (instead of tn, va, e-ips). if those are out of your budget or if you dont require such accuracy i'd go with an e-ips or va panel.
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short answer:
buy two 1920x1200 (or 1920x1080 at the minimum) monitors instead of one large 1920x1080(1080p) television.