If you think you will be interested in leveling some new characters post-cataclysm, you should spend your Triumph and any lesser emblems on Heirloom gear. With the conversion of the current currency to Justice Points, the cost of the heirlooms actually goes up quite a bit. As can be seen here:
Yes there are new heirlooms coming out that can be used up to level 85, but they are gained through the Guild leveling system. If you are not in a guild that will level to that point, then definitely purchase them now. Otherwise it's your choice.
The justice point cap when patch 4.0.3 goes live is 4k. Any points that you have accumulated over that value will be converted to gold. That 4k Justice points will get you at most 2 pieces of Rare lvl 85 gear in Cataclysm. Maybe it's worth not spending your emblems and letting them be converted so you have that justice point bonus going into end game Cataclysm. My thoughts are that if you cap out your JP's now and run dungeons while leveling, you're going to be missing out on those points (as you'll be capped). I'm planning on spending as much of my emblems as I can on things I want, and whatever I have left over I'll go into Cataclysm with as JP's.
As for Frost emblems, depending on the going price of Primordial Saronite on your server, you might consider converting them to that and selling it off for some gold.
I've heard rumored that the Gem vendor who sells epic gems for honor is going away come the 4.0 patch. Some gold could be gained now by converting your honor and stone keeper shards into epic gems, get them cut and sell them for profit.
As for other things to do. There are a number of achievements that are being removed/converted to Feats of Strength. If that's your kind of thing you might consider doing those quickly.
Sell off anything and everything you can if it looks like the going rate for it is high. Cut gems especially. Some things like enchanting materials and cloth may actually go up in price as new characters reach the 70-80 stretch and are leveling their professions. It takes a ton of Frostweave (for instance) to level LK tailoring. I imagine that stuff will get rather scarce when not everyone is running around Northrend. So if you have some bank alts, it might benefit you to save some of that stuff for a little while.