The Ti4800 doesn't compare to the Radeon 9700 Pro (the 9700 Pro is much faster and is a Dx9 card, instead of the Ti4800's Dx8.1 capabilities), but it's debateable which is the best card on the market right now. Some say it's the Radeon 9700 Pro because of its FSAA performance and actual availability, while others say it's the GeForceFX 5800 Ultra due to its faster raw performance, but it doesn't have the availability of the 9700 Pro. There's also the Radeon 9800 Pro, but that won't be in stores until early April.
But choosing the best card for you also depends on the rest of your computer - there'd be no use putting a Radeon 9700 Pro or GFFX 5800 Ultra in a machine using a P3 933 or 1Ghz Athlon; the processor couldn't take advantage of the cards' power, so you'd just be wasting your money on a more expensive card than you needed.