Just a little note - these thread suggestions are great but I hope you DO get to experiment! I am currently shopping for a long arm but have used a lot of these threads in my domestic sewing machine and love a lot of them...but they all have different characterisitcs depending on what look you're trying to achieve. So Fine is great because it's low lint and it's what many of the local long armers use...but it's also just as it's name implies - FINE! Cotton tends to be chunkier and gives a different effect...So Fine and Bottom Line (comes on prewound bobbins AND on cones) are great for blending quilting...also So Fine doesn't have sheen like some of the other poly's and looks like cotton...something I like when a shiny embroidery kind of poly isn't appropriate. The finer poly's are great for detail work - while I like heavier cotton for widely space all over edge to edge quilting. Just something to consider!
I don't think anyone mentioned Signature thread...that is supposed to be a good inepxensive yet quality thread. I haven't any experience with it personally but was hoping to try it out when I get MY long arm!
Also a lot of people also like Isacord - it's an embroidery thread but many people use it for quilting and it's pretty inexpensive. 5,000 (yard or meter I can't remember which) cones are something like $13. It's shiny though, no matte colors as far as I know.