I'm torn about which model to buy, anyone have any input?

HLT5076S is 56", 4000:1, and LED but the HLS5679W is a newer model and an a higher contrast ratio 10,000:1

Looking to buy tomorrow, any advice is greatly appreciated.

You said that in reverse. The HL-T has the 10000:1 and is newer (2007) than the 2006 HL-S model, which is 4000:1, LED from 2006. I have the 5679W and bought it merely because it was LED and was at a great clearance price. So I'd recommend it versus any lamp-based model which will cost you a bit more in the future.