Croatia - Zagreb, Dubrovnik, mid/south dalmatia islands
In Split - Buffet Fife fits the bill for an authentic Croatian experience (don't get thrown by the "Buffet" - it's all a la carte) and very affordable as well. Located west of the palace - usually busy but the hostess will find somewhere for you to sit even if it means you share a table with someone. Fun, loud, a bit smoky but great.
Also, Konoba Dioklecijan - within the palace walls. Hard to find but you'll come back once you know where it is. Great prsut - sit on the terrace and peer out the ancient windows onto the promenade below. If the owner likes you, you'll get a free glass of brandy before you leave :)
re: Elaine Snutteplutten
In Split, Black Cat Bistro and Sperun are good. In Dubrovnik, try Sesame, Restaurant Dubrovnik, Komarda and Gil's (high end) I think Nautica is way too expensive for what you get.
Also, the 2010 Gault & Millau restaurant guide is a dependable source and Croatia is part of the Austrian edition.
Best food market in Zagreb ... open stalls, lots of color, variety, is Dolac, right in the center of the city, near Ban Jelacic.
For very good local cuisine, on the pricey side, try Pod Grickim Topom. Actually not far from Dolac. Well worth the visit ... and a stroll around Gorni Grad (the old, or upper (Gorni) town).
A wide selection of restaurants with local and international (mostly Italian) cuisines on Kalciceva Street, in the pedestrian city center.
In Dubrovnik, seafood reigns. By far the best, and pricey, is Nautica. But lots available along the Stradun (the central street) and one street parallel to the East of the Stradun with lots of outdoor restaurants.