The West End is really just a part of downtown, it's just the older residential part of downtown... lots of leafy green gardens and beach access at the perimeter. There's not much office space in the West End which makes it more of a "happening" atmosphere, so to speak.
BTW, Yaletown is also fun... it's just east of the West End in the south-east corner. It's much smaller though and there's only one real hotel within the heart of the area (the Opus). But anyhow...
Haro Street is one block south of Robson Street, which is very busy with pedestrians - lots of shops and restaurants. The 1300 block of Robson has a lot of hotels on it. The blocks are tiny, so you're just going to be the street behind some big hotel towers.
Barclay Street is a few streets further back from Robson. There's Barclay Square with a lot of old heritage homes. You don't even feel like you're in downtown Vancouver anymore.
Either place is honestly fine... you could walk between the two in under 10 minutes.