If you love javascript and you are hunked on to prototype and you have never tried jQuery, then you need a cold shower. jQuery is an excellent Js library, I'll be using it from now on - as John Resig said "It is not a huge, bloated, framework promising the best in AJAX - nor is just a set of needlessly complex enhancements - jQuery is designed to change the way that you write Javascript."
jQuery is just about the 10KB in size and supports chaining which is excellent and it works with all the top browsers. Need I say more? Check out the demos here.