plan on doing higher than 10g?
I mean considering the LAN port on my computer tops out at 1gb/sec, I don't imagine I'll be breaking the 10g barrier unless my house gets struck by lightning.
It seems like CAT5e would definitely be sufficient for any home use. Unfortunately, I'm pretty sure my old cable is just "cat5" without the E. The first article that Janus linked says "Cat5 cables were made to support theoretical speeds of 10Mbps and 100Mbps. You may be able to get gigabit speeds on a Cat5 cable, particularly if the cable is shorter, but it isn’t always guaranteed." Meaning even a cat5(no e) is probably just fine, but it's not certified beyond 100mbps.
Since mine is old and frayed.... it's been stepped on, sucked up by vacuum cleaners, attacked by animals etc etc, plus it's that ugly pastel-blue color - I'm going to replace it. And yeah, since 2x 6-foot gold-plated CAT7 cables are only $5, I went ahead and bought a pair.
btw, thanks everyone for the information. As always, this forum has been extremely educational.