| well 200lbs is not to much to bench if you weigh 160 IF the rest of your body is up to speed with your chest (especially your core)... sometimes if you get stuck, switching up your routine(rep scheme, dumbells to barbell or vice versa, etc), taking a week off, or simply getting more intense should do the trick.
dips, as long as your body is perfectly vertical, are excelent for tricep development. and 2 iso exercises are good enough for triceps. but remember to keep everything even, meaning if you do 2 iso exercises for triceps, only do 2 iso exercises for the antagonist muscle (bicep). and to answer the Q about what gives your arm the most muscular look is kinda hard. the most size is easy, your tricep! it makes up nearly 2/3 if the muscle in your upper arm. but everyone loves a nice pair of guns.... for some more size on muscles maybe you should look into static (or isometric) exercises, they're not meant to be done alone, but rather worked into your routine... good luck! | 
