Well, here's a good chronological list for pre-season 9 stuff.
http://www.buffytimeline.com/index2.php
Might not have all the comics though. I think there might be a list on this site for canon comics.
I would suggest this reading list to start of with, with canon-ish comics;
-Fray tradepaperback
-Tales hardcover (has tales of the slayers and tales of the vampires)
-Angel after the fall tradepapaperbacks or hardcovers(exists as 4 volumes and one 17issue volume). Not to be confused with the rest of the Angel IDW main series, which is often also called After the fall, even though that arc only lasted for 17 issues.
-Spike After the fall tradepaperback or hardcover
-The 8 season tradepaperbacks (or wait until the season 8 hardcovers comes out. The first one will be out this summer)
-The namless Spike series by Brian Lynch, came in two hardcovers, vol 1 & 2.
There's lots more, but these are the ones usually considered as canon by fans. Of those, only Season 8 and Angel after the fall has been claimed by Joss to be canon.
You could of course go chronologically. Then I'd suggest buying Buffy omnibus vol 1-7 first then go from there.
Here's a good reading list for the IDW comics (since this was published there's been a hardcover called The End planned with the three last volumes of the main series released, but you don't have to think about those yet)
http://patrickshand.blogspot.com/2011/05/idws-angel-reading-order.html