5 wt fly line

I use Wulff triangle taper for cold water, but that's usually terrestrials and streamers. If you're casting more dry flies, there may be a better reccomendation.

As with your rod and reel, make sure to practice with whatever line you choose. It makes all the difference.

Rio Gold is the only cold water line I use but you'll pay $75 for it. I think if you're new to this you'd be fine with one of the more entry level Rio trout lines. I also find the Scientific Anglers GPX to be pretty good.

I have Rio, Scientific Angler, and Orvis.

I probably prefer the Scientific Angler, followed closely by Orvis.

I've never tried Wulff

I have several and if I remember correctly it's probably the GPX.

Would need to look to be sure though.

If you have a fly shop you can drop by, get them to help you select a line a spool it up for you. Spend money on your line. It'll last for years. Rio is a good brand. You got a good reel.