Boneless rib-eyes (aka Del Monico) are easy to do perfectly. Google for (many) recipes or do this: Pre-heat to 400F. Either whole or in halves place on rack in pan uncovered fat-side up. If doing two pieces be sure they're separated so both brown and seal independently. After 15 minutes, turn oven down to 325. Depending on your particular pieces, 1.75 to 2.5 hours, typically, or about 25-30 min. per pound up to five pounds or so, then depends on diameter. Use a thermometer. If you want "rare" (140) take it out when thermometer says 130. Same for "medium" (160) -- remove when at 150. Neither you nor your guests want it well done. Let it relax covered for 10-15 minutes before slicing.

Be advised there are lots of variations and they're easy to find by googling or looking at cookbooks. However, except for over-cooking, this is a VERY forgiving piece of meat. I have little doubt yours will be wonderful whatever method you choose.

Thanks asolo!

OVEN,
If you are going to cook to 160F, it will be VERY FAR from medium, (will be closer to shoe leather) IMHO. I cook my ribeye at about 300F (it will cook slower, but this lower temp allows for more uniform meat doneness. Instead of having the outer 1/4 well done, and the next amount medium and the center rare, unless you WANT it that way.) and then until internal temp reaches about 127F. If you want "brown crust" (for showing off) for flavor, I would recommend that AFTER your desired internal temp is reached, that you crank your oven up to 475F, and put roast in uncovered for about 15 min. You should have an internal therm that you can leave in the meat, IMHO, and I have some extras if you are interested.

As far as leaving roast in pan or on a rack, I leave it in the bottom. Makes for MUCH MORE FLAVORFUL gravy, IMHO.
Please feel free to email me at: bluelytes@yahoo.com I would be interested in how you chose to cook it, and how it turned out.

Regards;
bluelytes

Thanks bluelytes! I also started a thread at the Cooking Forum where I got some good responses too. I used cabogirl's method and my roast turned out absolutely gorgeous and so succulent. However, I think next time I might do what you do and not use a rack. I did miss having alot of pan juices for gravy.

Here is a link that might be useful: cooking forum thread