I've been looking into this myself, might be a little late for you post but I'll share what I've been able to find around the web concerning those same three processors, the same three I've been looking at.
First off let's start right here on tom's. You can get a bench for the TL-60 under the mobile chip section. It's performance is well... less that impressive. It's near the bottom but the important thing to drawl from this is that it's generally on par or better then the Core2Duo T7300 with the lower FSB. Why is that important?
The T575 is an OEM chip that intel launched without any fan-far and slipped into a number of mobile computers. From what I gathered from Notebookreview.com the T5750 is a cheaper to produce T7250 that runs at a lower clock speed, very similar to the T7300 at the lower speed. It's safe to say the performance difference between a T7300 and a T5750 have near identical performance.
With that in mind we can say the T5750 is a slightly (read microscopically) slower mobile cpu then the T7300 running a slow clock speed. Therefore the TL-60 safely performs on par with both of these intels and marginally out performs them in some tasks. So the T's are all pretty much the same. If your going to buy a laptop with any of these 3 chip types I'd ignore the cpu and instead look at what the other options are (Hard drive, DVD, wifi, RAM, video) to make a choice on which is best.
However when it comes to the Ultra ZM-80 allot of things change. Think of the TL-XX AMD chips as the old-guard. AMD has released two other Turion chips to replace the TL line. One is the RM and the other is the ZM. What's the difference? Glad you asked.
According to the AMD forums the RM is identical in architecture as the TL chips. However the RM comes in higher clocked versions and higher HT (hyper transport) speeds* and shares one important mobile aspect with the ZM. They run at lower idle clock speeds. The TL will throttle down to 800mhz at idle while the RM and ZM will drop to 500-600mhz which means longer battery life.
*Hyper Transport will not affect laptop performance.
The ZM on the other hand has TWICE the cache of the TL and RM cpus. In this regard the ZM will out perform them in almost every process (as Tom's has shown with their report on the significant of cache). However the ZM like the RM is fundamentally very similar to the TLs and subject to similar performance as same clock speeds. Because if this the "Ultra" ZM-80 running at 2.1ghz and the ZM-82 at 2.2ghz will be out performed by a Core2Duo T7500 running at the same clock.
Conclusion, if your thinking of buying a low end Core2Duo like the T5750 I'd take a look at the AMD Turion Ultra ZM-80 and 82. The AMD cpus also come with the ATI HD 3200 video chip set more often then not offering you some serious graphical performance.
For your needs, Photoshop, Cad and 3ds Max or not gonna get anything that runs these cpu intesive apps in a mobile platform at a resonable price. I run Photoshop and 3ds Max on my desktop which has a Core2Duo 6700 in it, nothing in the mobile platform comes near this unless you bump the budget up to something like the Acer Travelmate 6593. If your budget is tight i'd advise looking for the cheapest Core2Duo Penryn chip (P8400, P8600, etc) system you can find. If it's still outside your budget then go with whatever sytem either a AMD Turion ZM or Intel C2D T5850, T8100 that best suits your ram and disk requirements within budget.