Congrats on your speedy.Trevi PM is a beautiful bag.You can carry it on the arms or on the shoulder.It has both straps but it is on the heavy side (atleast according to me).But other than that, its a great bag.Eva is totally different.http://www.youtube.com/watch?v=It3IHhMUTGc reviews eva clutch.
SInce you have a speedy 30, for a variety in bag size, I'd get the Eva so you'll have a small bag for quick errands. I have the Trevi PM and it's a great size - it's very similar in capacity to the 30. I sold my damier speedy when I got the trevi PM.
Thank you all for your suggestions! Looks like I'll probably get the Eva and wait on the Trevi as most of you suggested. I really like the versitility of the Eva and since most of my bags are rather large, it would be nice to have something smaller for a change.