Using the search feature will find you lots of good info so please definitely do that, but there are two companies manufacturing new tape currently: ATR Magnetics and RMGI.
ATR makes one formula which you can calibrate to pretty much whatever you want up to +10; some hit it at +6 though I like +9 and think print through can be an issue above that especially if you aren't being pretty conservative with your levels. I've used the ATR 1" for indie rock and acoustic folk projects; it sounds very good and the reels I've tried seem better slit than the 2000's-era Quantegy tapes I've used, but there are a couple caveats: 1) you have to run it back and forth a couple times and let the excess oxide run off, keeping your tape path clean as you do it, and 2) they let a bad batch get out in autumn of '10; avoid any ATR tape from that time and you should be ok. ATR's customer service is great.
RMGI does modern versions of former EMTEC formulas--SM900 (+9 tape), SM468, SM911 and its variant LP35 (+6 tapes). I haven't used them yet, but others here have discussed them so do a search. As with the ATR, buy fresh reels and you should be ok.
Take a look at the Sticky Shed thread at the top of this forum for info on what to avoid; probably at the top of the list of tape not to buy is Ampex 456, though Quantegy-branded 456 should be ok, as should any 499 or GP9--but those Quantegy tapes are about 8 years out of production so you'd be getting them new-old-stock or used. On a side note, I question the slitting of 2000's-era 499 and GP9, I've found I have to wind fresh NOS reels of them back and forth a couple times to let them "shave off" a little on my MCI machine, though this may not be such an issues on other machines, I dunno.
This weekend I will be recording the same folk band to some new-old-stock GP9 that I did to ATR this spring, so will be able to draw more comparisons between the two.
