Being a meteorology person, here is what is going on with the strength of Rita... and nothing is certain right now. There are still about 32 hours remaining until landfall, which gives the storm plenty of time to either weaken or re-strengthen.
Here are the factors:
1. Category 5 hurricanes never stay cat 5 for long. Eventually, the inner eyewall becomes so small and intense that the storm chokes itself and ineviteably loses intensity as the eyewall re-forms. This usually happens just under 24 hours after it becomes a cat 5.
2. Only 1 cat 5 hurricane has had the chance to reform after losing it's initial strength, "Allen" in 1980... and that storm fluctuated from 170 mph down to 135, and then back up to 180, down to 140, and up to 165. Cat 5's can and will reform if given enough time... Most others run into land or wind shear first. Rita has warm, open waters for 400 miles in front of it.
3. Looking at the satellite loop, Rita has just finished choking itself. It will remain a cat 4 until the eyewall reforms, which could take anywhere from 3 hours to 3 days.
Conclusion: watch the satellite picture. If the deep red convection begins re-gaining density, which it probably will tomorrow around 5 pm, watch for the storm to re-strengthen. If the eyewall remains ragged as it is now, Rita will hit land as a cat 4 or a strong cat 3. If it reforms, Rita will rapidly intensify and hit land as a cat 5. We can only hope for the best.
Tomorrow afternoon will be the true deciding time. There are still 400 miles of 85+ degree water between Rita's eye and the Texas coast, so it is all down to how fast the storm can reorganize itself.