There's a few factors to consider regarding your question. Do you fish mostly stillwater or streams? Also, what ballpark were you considering in spending on a line? There's a ton of good lines available out there, and something to consider is what brands your local shop carries so you can get quick service if you ever need it. Also, there are gems and duds in almost every line manufacturer's offerings...so depending on which particular type of flyline you're looking for...etc. etc.
Do you chironamid fish? For chironamid fishing, the best floating flyline that I have personally fished with is the Scientific Anglers XPS. This line is not meant for long distance casting, but is very supple and has very low or no memory. You can easily lay out a medium distance cast with it, and it lays flat on the water with no kinks. Surprisingly, the least expensive floating line that SA offers is also quite good for this application, mainly because the short belly that enables rookie flycasters to feel their rod load is also good at throwing long leaders. If you're interested in that one, it's called the SA Headstart.
Also...your choice in lines really depends on which particular model of Sage rod you end up purchasing. If you buy the faster action Sage rods, I would highly recommend matching it with the heavier SA GPX or similar line.
The absolute best sinking line that I have ever personally used is the Uniform Sink series from Scientific Anglers. They have a skinny diameter that just shoots through your guides like nothing else, and they sink the way they're designed to. I love these lines for fishing lakes.
For a clear sinking line, I use both the Cortland 444 Clear Camo (which is a slower sinking truer intermediate line) and the Cortland 444SL (which is really more of a typeII line than an intermediate). I have tried the SA Stillwater clear sinking line, but I find that they tend to crack quite easily. I have no such problems with my Cortland lines.
The most versatile line that you could buy would be a multi-tip line. While the initial purchase cost is high, it is like buying 5 quality lines at once, at less than half the cost. You will also save a lot of money in not having to buy extra spools. And you will not miss carrying all those spools in your vest. These lines are also great in stream fishing, where you often need a couple of different sinking tip rates to work a nymph well (even though technically you can sort of do all this with a floating line and some shot or weighted flies...but less effectively and with more hassle). Also, replacement tips are available for a reasonable cost...so a good multi-tip should last you a long time. I have a multi-tip line for every single one of my rod weight setup except for the lightest two, which are the 4wt and 2wt. I use RIO Versi-tips almost exclusively.
Hope I've given you a starting point. Good luck!