Last week Dr. Marky Roden gave some excellent insights on using jQuery with XPages on the Taking Notes podcast.
I really believe that anyone who is doggedly devoted to doing everything in Dojo just because "that's what comes with XPages" is missing out on some serious developer productivity improvement and cool UI enhancement opportunities.
Marky has been doing a great job espousing and teaching jQuery at Xomino.com but this podcast is a great discussion that really answers a lot of questions XPagers commonly have about trying jQuery.
Give this one a listen this week. You'll be glad you did. Even if you decide not to use jQuery at all, you will be better informed and feel much better about your decision to use/not use jQuery.