HDMI 1.3 offers the following "possible" enhancements:
Output of high resolution soundtracks (uncompressed) for decoding in an AV receiver/Amp
Deep Colour (data sent with a greater than 10bit per pixel colour resolution...8bit is standard)
Lip sync correction
CEC link
The HDMI 1.3 spec is a bit misleading though since the Deep Colour and High def sound do not have to be supported to be considered 1.3 compliant.....you just have to look at the TVs spec to see if it's supported. I'm not sure about lipsync and CEC, but some manufacturers are explicitly adding these to their specs anyway (check out toshibas latest Z series).
So how do these features affect your TV?.....
High res sound is not something your TV will ever make use of, so that's pretty irrelevant for buying a screen.
Deep Colour is a bit of an unknown....the new HD format disks don't support it at the moment and there is some confusion over whether they ever will be able to without making all the existing hardware obsolete. Besides most current TVs will only display 8bits per pixel colour anyway....so it's pretty redundant at the moment.
Lip sync correction sound useful and it may prove itself so, but its a pretty basic system where the transmitting appliance sends a bit of info to the screen telling it how long it takes for the video data to pass through all the DSP circuitry. The TV can then apply that amount of delay to the sound to keep everything synchronized nicely.
CEC link allows connected appliances to talk to each other so you can have some kind of unified remote control (ie turn off the tv and the dvd player gets told to turn off too). I haven't seen any reports of this working in the real world yet, but again it may be quite useful.
Unless the TV you buy actually supports deep colour decoding to the screen, HDMI 1.3 won't buy you anything.
If you need a TV now, I'd go with the 100Hz over HDMI 1.3. The new HDMI spec is more of a future thing and it may never be fully utilised. Sorry if this info is confusing, but it really does confuse everyone....I work in the consumer electronics business (design) with HDMI and even we don't know exactly where this stuff is going or how useful it will be
