I've said it before and I'll say it again; Melbourne is the only zoo in Australia with a half-way decent collection of monkeys.
The reason, I suspect, is that Melbourne doesn't shy away from displaying monkeys behind mesh (i.e. in cages.) Most zoos are a bit precious about this, and don't want to keep their monkeys "behind bars". The trouble is, monkeys are such agile, intelligent and, lets face it, devious little critters that they tend to "go walkabout" if not in a cage.
(Taronga's macaques used to get out all the time when kept in the old pits just north of the old elephant house.) Now Taronga's got hardly any monkeys at all.
O.K. Patrick, so we agree that the hamadryas baboon enclosure is an eyesore, and that the mandrill enclosure is good (yery good, in fact), but let's not ship everything out to the backblocks just yet. When you say that the baboons are underappreciated I assume you mean by zoo authorities - they certainly are appreciated by the public any time I've been there, although THAT enclosure certainly cops it's share of criticism.