Don't take their advice. Do your research on brand names.
A 7 page thread and still havent decided? jeez how much research do you need for an external? The only question you really need to ask is: are there any lemons on the market atm, and as i said, no.
And whats wrong with the advice I gave, thats pretty much the checklist you'd go through for buying an external, the one i missed out was 2.5 vs 3.5 for portability.
please tell me what more do need to research for an external
EDIT: and pricing for a 3tb should be around 150ish, 2tb are around 100ish. (usd)