Make sure you get the thread from diygear, he lists what it actually is, and it's all the good strong stuff. The thread prices are great, I'd get one big spool of each color he has, plus the strong thread, tera 40 I think it is, which you want for the high stress connections like straps. Those big spools last a long time, and the stuff you find at fabric stores if it's the gutterman is the thin stuff, not anything you'd want to use for a pack.
I wish diy would carry more colors of thread, but he seems to be adding more slowly, but a full range would be great, I'd buy them all, it's worth it, stuff looks nicer when the thread colors match.
owfinc also carries the big spools of some colors, gray/black, which are in fact the same type as diy carries, but I don't believe you could find that fact out by reading anything, but the 765 yd spools, which are just right, that owfinc has are the same type as diy.
Owfinc has the nice 4 oz /yd black mesh. owfinc has sort of expensive shipping, so if you get stuff from them, make sure you order a lot to make it worth it. I think they have the cheaper thin ladderlocks, but I'm not certain.
Rockywoods has a great selection of colors of oxfords and 70d nylons, plus the dimensioan polyant stuff, and their prices are good. They also have different colored webbings, the only place I know that has that. Their matching hardware though is very heavy, albeit super strong.
I agree, get way more webbing, hardware, than you think you need, it's good to just have it around, and it's very hard to find stuff of good quality locally, if you can even find it at all.
Note that zimmerbuilt sells very good quality ladderlocks, other sources use the cheap thin kind, if they have pics you can see the difference, the type zimmerbuilt and a few others sell are more curved and much nicer, albeit a tiny bit heavier, but do you really want to use a smaller lighter one for a key connector?
zpacks has nice stuff too re connectors and webbing and all that. 1/2" grosgrain might be harder to find, I'd buy that, it goes fast, and you might not find it locally.