Frangos&Frangos is overrated, IMHO, but it's very popular.
Mrs B gives Mercarto a good rap, but I wasn't invited
If you can get a bit out of town, Captains Creek Winery / Goldfields Farmhouse Cheese, at Blampied, is well worth a visit. They have a weekend lunch menu.
A bit further out of town... and into my home turf... Lydiard Wine Bar in Ballarat. Exceptional eating, in a Thai/French seafoody local/seasonal-ey kind of way. Damien, the chef, got one of them Michelin tyre/star thingies at his previous gig in London. If it was Melbourne, you'd book months in advance to pay $150 for his degustation... but since it's in Ballarat, you can just turn up (most nights) and pay $70.