I think the game looks good and I am excited to play it but would those who have the game weigh in on this question: If I am only going to be playing it primarily for single player (or tell me why the game is good enough to convert me to dealing with jerks online) is the game worth a $40 purchase?  
 
Thanks chaps!

I honestly couldn't fathom buying Blur if you weren't going to play multiplayer. That's so much of the game's fun, and the singleplayer is even blander than the old Project Gotham Racing singleplayer modes. The multiplayer's completely chaotic, especially with a full twenty players, and the action gets completely frantic with weapons being flung around and cars sent flying. It feels like a fast-paced fight, and there's not much shame in finishing in any position other than last.
 
I'd suggest giving the multiplayer demo a try, and tune the voice chatter out if necessary. If it doesn't trip your fancy, it's definitely not worth $40.

The single player is nothing special. The online, however, is a lot of fun. I played single player for a little while to get my bearings and then hopped right online. Its definitely the best part about this game.

I played the full single-player to get most of the achievements, and I wouldn't recommend it for solo play.  I'd totally recommend the multi, but not the single.  Split/Second sounds more entertaining solo, but I have yet to play it.

No. Let me describe for you my single player experience. I load up the first event and manage to place first and move on to the next. In the next event however I only manage to place 11th or so. Faced with the prospect of the same race, I decided to never play the single player ever again.

Blur is like Call of Duty games: the single player is solid, but you buy the game for it's awesome online play. If you don't plan on playing Blur online, I'd recommend to save your money. The single player is decent, but not amazing.

I would say no.

I don't see how you can have a bad multiplayer experience with Blur. Don't use your mic if you are worried about assholes. That way, it'll be like single player but way more fun! 
 
 It's a game where you try to fuck over other players as much as possible. It's not like you are going to get team-killed and teabagged or something. 

no

Im working through the single player and loving it. Ive just come off and its 4:30am currently... Really didnt want to be up this late but I couldent put it down!
 
It seems exactly the same as mp, but without the lag. (Nothing bad, just sometimes other cars teleport.)