I know I am just echoing others, but
I've found that one of the
best parts of the game is Neighborhood Missions. While we are all
waiting for new content, I have a feeling that this feature goes
largely untapped. There is a boatload of content in these missions
containing subplots that provide insight into the workings of the
Matrix and the overall story. Each mission contact has his/her own
little story that includes working with or against other mission
contacts. Naturally, if you treat these like standard missions and run
through them as quickly as possible without reading, you're going to
get no more enjoyment out of them. But, if you take the time to
understand what's going on, I think you'll have fun and be compelled to
continue with the next mission.
For starters, it always helps to know a little about the characters. I suggest you read about The Elements, then run missions for each contact in Richland. From there, you can complete the rest of the contacts in Richland, or move on to The Spectrum in the Barrens. International District and Downtown provide a variety of enjoyable characters as well.
Sugaree has prepared excellent Neighborhood Mission reviews (check out her blog). Click on the contact's name to see the review, when provided. This table is based on the one at rumbaar.net (Thank you Draconis).