Apologies for the late reply my frnd! Was busy with CWC telecasts. :)
Anyways, there isn't much difference between LE5500 and LE7500 except the later sports 2ms response time and better viewing angles against 2.4ms response time of LE5500! Here is the specs comparo: http://www.plasma-lcd-crt.com/compares/lg_32le7500_vs_lg_32le5500.
If you're getting Le5500 at better rates than i'd suggest you to go with LE5500. Its gr8.