Well, with the Balkans, it depends what you're looking for. I do like the area, and I'm a big fan of cevapcici with ajvar, and various forms of burek, as well as the Turkish-style (never call it "Turkish"!) coffee served everywhere - and the interesting Italian-Slavic mix in Slovenia.
Ljubljana is a student city, and this is obvious when you visit. It's a small city, but a pleasant the quirk one. The Julian Alps are stunning, particularly Bled and Bohinj, and easy to reach from the city. The tiny coastline packs a lot in, from old towns like Koper to resorts with regrettable amounts of concrete.
Croatia is no secret any more. The last time I visited was just after the war, so I pretty much had Split and Dubrovnik to myself (as well as a rather battered Zagreb). Zagreb is a quirky place, again, with a very Central European feel. Split is small, but the way the town is woven into Diocletian's palace is fascinating. Dubrovnik is stunning and remarkably well preserved, but you need to go well off season to miss some serious crowds of tourists. I've never managed to make it to the islands.
However, perhaps the most interesting, for me, was Bosnia. I would love to go back. I took the bus from Dubrovnik through the wonderfully kitsch pilgrimage site of Medugorje up to Mostar, which was still a sad sight, with the Stari Most in pieces, and ethnic sensitivities running high (you have to order a coffee differently in different parts of town, if you're trying to speak some form of what used to be referred to as Serbo-Croat). From there, another bus up to Sarajevo, another city hit hard. I stayed in an old railway carriage near the station (the walk over unmarked land was a little unnerving) and loved wandering around Bascarsija. I understand the mountains are now clear and safe to visit - they provide a wonderful backdrop to the city.
So it's definitely an area I'd like to revisit.
As is Romania, for that matter. I did a fair bit of work in Bucharest and Timisoara, and managed to get some time to explore the corner of Transylvania around Brasov. The train journey there from Bucharest alone was worth the journey - they're a sociable bunch of passengers, and the rural views from the windows could have set you back a hundred years in time.
So, there's plenty around there I'd like to revisit as well. And perhaps head down towards the other ex-Yugoslavian states - places like Sveti Stefan and Lake Ohrid.