In general, all these terms mean the same but vogue at different eras. 饭馆 literally means rice hall, 饭店 rice shop and 餐厅 = lunch hall. The last one is the type that more vogue than the first two traditional ones. In HK, they serve both western and Cantonese dishes or a fusion of the two. You definitely don't see swirling dragons and flying phoenixes as decor. There are two more types of restaurants. 酒店 and 酒家. In the olden days, they sell wine as the main commodity. However, nowadays from observations from I see in Chinese restaurant names, these are the fancier ones and at higher prices too!

饭馆、餐厅、宾馆、饭店，档次越来越高。饭馆一般只能吃饭，价格比较低；餐厅的档次比饭馆高一点，也只能吃饭；宾馆可以吃饭，也能够住宿；饭店的档次很高，价钱也很贵，可以住宿、吃饭，也可有其它娱乐项目；例如：北京饭店、建国饭店、莫斯科饭店......

当我们说“饭馆”时，一般会在前面加个“小”字，也就是“小饭馆”，一般指规模很小的廉价饭店。“宾馆”是带客房的。“餐厅”一般指一栋楼中对外营业的提供就餐服务的地方，比如：“XX宾馆的餐厅”。“饭店”可以是指对外营业的提供就餐服务的场所，或者是对外营业的同时提供客房与就餐服务的场所。“大饭店”的意思与“宾馆”大致上相同。如果一家宾馆取名为“XX大饭店”表示它的老板自认为这是一家高档的宾馆，但高档的宾馆不一定都取名为大饭店。

饭馆一般只能吃饭; 餐厅一般是职工吃饭的地方, 也叫食堂; 饭店和宾馆一样差不多, 可吃饭也可住宿. 饭店是比较老式的说法, 以前没有宾馆一词, 吃饭住宿统称饭店. 这几个词前面加小比较便宜,加大则比较昂贵.

饭馆 = 饭店 = restaurant (separate building) 餐厅 = restaurant (inside some building) 宾馆 = inn