This is just so spectacular, funny, (insert multiple glorifying adjectives!) and the concept alone gives the wall an A+. At a first glance the wallpaper is funny and if I didn't read your comment I may even have missed spike in the reflection but that edition makes this a serious laugh out loud. Within the glorifying of the concept I'm not going to ignore the artistic aspects.
From your comment and the wall it looks like you've achieved exactly what you planned to do and I'm surprised at the harmony between having a real world reflection in the window and maintaining the anime feel. Also great job on getting spike out of the window scan, showing the original makes your efforts twice as recognised :D. My only critism would be that it appears that Spike himself has become slightly transparent in the reflection.
I've never actually been aware of seeing a starbucks before but regardless I like the look of the logo on the window. A beautiful, highly enjoyable wall and definately a favourite, a favourite among favourites!
Edit: Runs to DA for a resolution my screen will enjoy more X-P
