I would have to say I had two wow moments:

1. using the conversations app. still love it and is one of the reasons I bought the phone (simple but essential for me since I'm an SMS addict - which is why I'm also loving this keyboard although wish it was 4 row so i can get more space for my bear paws plus fit in some extra buttons).

2. last week my laptop had to go for repair and I had a lot of downtime so at home I used the N900 for 3 days straight as a primary pc. using WLAN hours on end while connected to TV-out I was able to chat, email, read news, browse this forum and stream movies/music all from this sleek, tiny device. it was definitely a wow moment for me.

still loving it. oh and also in case noone else has stumbled on this yet I've discovered a HUGE improvement in battery life when I charge via my laptop. someone else on here mentioned "slow charge" vs "fast charge" and it's definitely true in my experience. USB charging has made a noticeable improvement in battery life for me in the past 2 days.