She's a beauty.
Personally, I think the CBR1000RR is a very nice bike, but I'd keep the RC51.
After all, in the sportbike arms race, the current CBR1000RR will only be as good until the 2011 comes out. Then it's yesterdays news.
Whereas the RC51 will always be what it is, the last of the old-school HRC designed bikes.
I also have a Hayabusa, and if I had to make a choice, the 'Busa hits the road.
The difference is the 'Busa I got because I got a really good deal on a 1 year old bike with only 890 miles on it.
The RC51 is the bike I wanted a long time. In this decision, I follow my heart.
Just make sure your RC51 goes to a good buyer who will appreciate it.
Please don't sell to some squid who will only stunt it or fling it down the road in pieces.
Give it a good home.