Best LV line for an everyday bag?

I think the monogram canvas and epi leather (in that order) are the most durable of the LV line. However, the regular epi (not the soft one) can be quite stiff and will take some time getting use to.

I agree with mrsjimmyh about the Popincourt Haut. You can't argue the fact it is a shoulder bag, which is practical for everyday use. Let's face it, you will get tired at some point carrying the Speedy by hand.
I saw 2 girls at school carrying the Monogram Canvas speedy 25 today and I WANT ONE NOW TOO! They (the bag, not the girls lol)are sooo cute!! But I'm waiting for the Damier Speedy to come out though... hee hee.
The best line (in terms of material?), would probably be a damier bag. Since it has no vachetta on it, you don't have to worry about water stains, they are weather proof ! With monogrammed canvas, you have to worry about rain or snow, and some people (myself included) don't really like the patina.

I'd have to second Noriko's popincourt haut suggestion though, I LOVE shoulder bags, and the speedy just isn't as practical since it's a top handle.. unless you have ridiculously skinny arms.
Well...since I have both (well, i have the 30) I'll have to say that it depends on your personal preference. Do you like to carry bags or have them on your shoulder. I use both just depending on my I have tons of running around to do, will I be carrying a lot, etc.
I love my Speedy, but would have to say go with a shoulder bag for every day. I have a kid and a dog and when I'm out with either or both, I definitely need both hands free! The Popincourt Haute is a very nice looking bag. I have the Batignolles Horizontal and the Petit Bucket, and both are also great shoulder bags.
Or...although its not always fashionable, get the speedy and the shoulder strap, attach the strap only when necessary. I have done that over the years when my arm/hand looses circulation!