In general, I would agree with those who have said just hold on to what you have. It sounds like you are happy with the car, it is still in great shape despite the rear collision (63k is like new for a Lexus, BTW.. you could probably drive it 5 times that amount if you wanted to as long as you keep it well-serviced).
It is true the value of used cars is up right now, but like most market fluctuations, it is a two-sided story, because there are supply chain issues with some electronics parts that come from Japan due to the tsunami. This means it is also harder to get a good deal on a new car (by that I mean there may be less haggle room in the price, or it may be harder to get the exact options you want which would result in accepting a model with features you don't want and you end up paying more for them, or you can't get the color combination you really want, etc). I can confirm this situation is real, because my girlfriend is in the process of buying a new car right now and its very different than a year ago when I bought my car. Many of the dealers of Japanese makes don't want to budge off of MSRP.
So, the only way you could really make the market situation "work for you" is if for example you were getting ready to go on a one-year bicycling expedition across Europe or something, wouldn't need your car for 12 months and knew that you wanted to get a new car immediately on your return, then it might make sense to craigslist your current car and go car shopping when you got back from the trip.
I've always felt that buying a new car every 3-5 years is generally a blatant waste of money. I tend to buy a new car about every 7-8 years, 135k miles, or whenever it "feels right". Usually it feels right when the warranty is long gone and the amount I start spending on repairs/maintenance represents a significant percentage of the total resale value of the car. In truth, it is almost always cheaper to continue to repair your existing car than it is to buy a new one. At some point there is a "convenience factor" that tends to get lost late in the car's lifecycle, for example if I need to start rescheduling important meetings at work because of hassles associated with car repairs, then it becomes a problem that extends beyond quantifiable repair expenses, and it just makes sense to get a new vehicle.
Sounds like you're nowhere close to that point yet, and generally happy with your car, so unless you've got tons of money to burn frivolously, I'd hold onto it.
To all this I will add one caveat. The integrated electronics systems in many cars (not just luxury models) can be extremely expensive (think along the lines of $4000-8000) to repair outside of warranty. Some of these systems are so integrated and non-modular that if you have a problem with the nav system, you need to replace the entire climate control system! This is one reason I opted out of built in navigation and got a good Garmin portable when I bought my Lexus new last year. However, since it seems you are one that prefers built-in nav, I would say that considering a new car before your 100k warranty runs out is not the worst strategy I've ever heard. There are many web forums that are very helpful for researching what, if any, expensive repair issues your particular year/model is prone for, and at what time or mileage interval. The one I frequent is clublexus.com.. they have individual boards for each model.
Good luck.