What would the be brands/manufacturers I should focus on? or rather what should I stay away from?
There are many brands of British, Italian, French, Japanese, and US bikes to choose from. There's a warm place in my heart for old Univegas, and my head perks up whenever see some of the old offbeat Euro brands--Mercier, Bottechia, Falcon, Bertin, Follis, Frejus, Cilo, LeJeune, and so on. In my opinion, down-market Raleighs and Peugeots are overrated and tend to be overpriced.
Find something that fits you and complements your aesthetic sense.