asking for preferences on car parts is the same as asking whether one hard disk manufacturer is better than another (maxtor, seagate, western digital etc). Speak to enough people and you'll find several who have had big problems with each item.
since your existing water pump, timing belt, tensioner etc have all lasted 100,000km i would be tempted to put standard parts straight back on unless your motor is significantly modified. common advice seems to be to do water pump, tensioner and idler when you do the timing belt because it's a pain in the bum to pull it all apart again if you have to do them later on.
so yeah, just do ONE service and fix the lot. depends how quickly it's leaking, as to whether you do it all now or you can get by for a month with regular top-ups. if it's a significant leak then do it soon because you don't want to forget you're losing coolant and overheat your engine