Better engine, SportShift transmission, better looks, better resale value, better dealership service, bigger in all aspects, two 12V outlets, Vehicle Stability Assist (VSA), nicer fit and finish...it's basically a nicer Accord, but it's way more than that. You need to test drive both to see if the price difference on the TL is worth it.
Keep in mind there is a brand new redesigned TL (It hasn't changed much since 1999) coming out in Fall 2003, and the Accord is a brand new model...so the Accord has much of Honda's newest technology
Chris