Eluxury sometimes if I can't find the LVs I'm looking for at the store...otherwise I alternate between buying things at whichever store I'm closest to at the time (mostly South Coast Plaza or my Neiman's boutique for Chanel, Fashion Valley boutique or Neimans for LV).
Ala Moana is Hawaii's biggest mall and home of what I call my favorite shopping corner: Tiffany, Coach and LV all within 50 paces of one another. The LV and Coach boutiques were just redone. Chanel and Gucci are about 100 paces nearby as is Neiman. In Waikiki Coach built a beautiful flagship store and the Waikiki LV is great too but parking is awful in Waikiki and not really "local" friendly.
LV = ELuxury or 866-Vuitton (won't go into a store and be treated like crap! The "866" reps are so nice and helpful and helped me get the LAST item available in the country!)
Coach - my local Coach store. Love the SAs, they love me ( I think!) Nordstrom - (Chloe) and a couple of Hobo, Furla and Juicy.
E-Bay - ONLY from trusted sellers I have dealt with for a while.
Private parties - people I trust. Nuff said.
Marc Jacobs direct thru the SF store. (DH actually did but made me a believer cause they treated him so well!)
Most of my bags have been bought from Holt Renfrew but when I go to the US, I try to buy at least two bags from the stores there during my visit. But since joining tPF, I have started to purchase some bags from recommended Ebay sellers and some tPFers. I just made my first purchase from NAP today.
Selfridges, Harvey Nichols, Liberty - I like a selection as I am not attached to a particular designer and prefer the less initimidating environment to the specialist boutiques of Bond and Sloane Streets. Net-a-Porter, Matches and Browns have served me well when I am ready to buy on-line (i.e. when I know what I want). Ebay has tempted me, but seems high risk and friends also tempt me but are very low risk!
I wish I could always buy in person, but there is little shopping where we live now. When we return to Chicago, I check out the stores on Michigan Ave.--Neiman Marcus, LV, Bottega Veneta, Cole Haan,Gucci, Chanel, Bloomie's; and on Oak St. I look at Tod's, Prada, Kate Spade, and Hermes (scarves and ties only).
Online, I've shopped Neiman's, Zappo's, Bottega Veneta's site, and the eBay sellers that I trust.