Start with a GOOD mount. The Springfield one ain't gonna cut it!
Get one from Smith Enterprise, Sadlak, Bassett Machine, or GDI. Smith has a great deal on their Weaver mount, and I think it is the best deal in an M14 mount in this day and age. The Bassett is newer to the market, but has been well received. These are bolt-on/removable mounts and won't permanently alter the gun, or decrease the value as mentioned above.
After that, scopes are a very personal thing. it's going to depend on what kind of shooting (target vs. hunting, 100 yards vs. 600 yards, etc.). As a target shooter, I like bullet drop compensators and forgiving eye relief. Things like tactical turrets and adjustable objectives come secondary to me. You just have to decide what is important to you. For example, people swear that the Leupold MkIV series is the best piece of glass ever made, but I find the eye relief too unforgiving at higher magnification. I also find that they are overpriced for what you get. There are plenty of scopes out there that offer comparable quality for less money. I recommend Nikon Monarchs (BDC reticle), Burris Signatures (Ballistiplex reticle), and Bushnell Elites, but that's because I am a working man and don't think that $1500+ scopes are really
worth the difference for 99.9% of shooters. Zeiss makes kick @$$ scopes if you can swing the extra cash, or if you can get a good deal on one.
It's really going to boil down to what your needs are, and what you prefer.
