I started off with exclusive pairings for most characters - Willow being the only one where I couldn't choose between Oz and Tara - but the more I considered it, the more I found myself liking at least 2 pairings for several characters. Now, the only characters I ship exclusively are Buffy and Angel (because I love Bangel that much), Doyle (because we haven't really seen him interact enough with other characters to ship him with anyone but Cordy) and Cordy (because I just don't really like any other couple with her in it).