I'm trying to build mass, and have been using a reclined bench press here in my home.

My question:

Which would result in a better workout....doing 10 reps of say, 100lbs, or 30 reps of 50 lbs?

I'm not a huge guy, so at the moment those are my limits on the reclined press. The 30 reps of 50 leave me feeling a lot more drained, if that helps.

Switch to a flat bench or very slight incline and do 3reps w/ 200lbs instead of 10/100lbs or 30/50reps if you are looking for mass. Your limit might be 100lns NOW but your goal should be to increase it to 200, 300 or whatever. Mass is all about continually increase the weight you lift ;)
Messing around w/ incline/decline is nearly pointless...stick w/ flat and work on increasing the pounds you move from point A to point B.

I will really stress that benching alone will not give you any of the results you are looking for.  Your routine or split should be centered around squats, deadlifts, and bench (the big 3).  Rep ranges are almost totally induvidual and certain people get better results with certain ranges however in my personal experience anything over 8 is cardio [:D]

Also your diet will be the determining factor in adding mass or cutting up so make sure you are getting enough cals and all your macros.  500 extra cals per day equates to about a lb of mass a week.

"anything over 8 is cardio "

BRAHAHAHAHA!! That should be a mantra, Bro! Been saying that for years :)
Good advice about the BIG 3...I should have added that instead of commenting soley on benching. Where are you at in TN? I used to live in Antioch and worked at Gold's off Bell road...trained all over though w/ various competitors. Ever been over there?

Hey GMP I live in Harrogate about 1 minute from VA and KY.  Ive never been to Antioch before.  Do you powerlift?  Im thinking of getting into it once I get more experience, strength, and size under my belt.  Are you on any weightlifting boards?

Powerlifting is out of the question for me...permanant fracture between L4 and L5. I even have to be careful w/ squats the last 4yrs. I used w/ compete in bb'ing...still train but have no desire to compete anymore. I frequent a couple boards, still mod some over on getbig.com ;)

Best of luck w/ powerlifting!