West Ham away 2007 as many have mentioned was probably the best as it really felt like it was a new start after a pretty bleak 18-24 months.
Blackburn away 2009 was good as it was like a new team, Newcastle at home under Pellegrini too felt like a new start after a shit end to the previous season, West Brom 3-0 in 2015 also pretty good when Kompany scored and stood on the advertising boards in front of the away fans.
Any of them over the past 5 years have been pretty great apart from Spurs last season. Brighton, Arsenal, West Ham. In fact, we don't play at home much on the first game do we?!