Since someone posted the Hungarian Parliament (which is one of the most amazing structures on the planet) I guess you won't mind a bit of Canada in this discussion. I think they're all pretty well done, except for Yukon's.
Confederation Building, the legislature of Newfoundland and Labrador
©
Dreadful Photography
It's apparently based on a Bauhaus interpretation of the national Parliament.
It is located just off a highway, and surrounded by parking lots.
Province House, the legislature of Prince Edward Island
©
laze_brian
It's looks more like a city hall but PEI
is tiny.
Province House, the legislature of Nova Scotia
©
reddoor.realty
The oldest parliament in Canada, it was built in 1811. It is like Massachusetts capitol, no green space around it, it's just there.
Legislature of New Brunswick
©
John MacDermid
The French influence in strong in this one. It's my favourite of the Atlantic province's legislatures.
Assemblée nationale du Québec
CC BY NC OZinOH
Hard to find good pictures of it apparently.
Queens Park, the Legislature of Ontario
©
Capitolshots Photography
In the right light, it looks pink. It's a very dark and menacing looking building for a seat of government, I think. I think it's the only Richardsonian Romanesque Revival legislature in Canada/the US.
The Prairie legislatures are more like American style capitols, with the classical architecture and central dome.
Manitoba Legislative Building
CC BY NC ND Herman H. Cheung
The tallest (77m) of the provincial parliaments, the building's architecture is loaded with Masonic symbolism and the façade is Tyndall limestone, which tends to be more fossils than stone. It's a very interesting building to explore.
Saskatchewan Legislative Building
PD,
Wikimedia Commons
It was built very large, anticipating population growth that never happened.
Alberta Legislature Building
PD,
Wikimedia Commons
It's a unique colour.
Parliament House, Legislature of British Columbia
CC BY Wikimedia Commons
It's even better
at night.