Wow, you people are funny. And here I am taking all mine into the PO, using the scale in the lobby, and if they are off by .1 oz I get in line (little to no lines at my PO anyway) and pay the extra 24 cents for a stamp to tack on. I always assumed they would get sent back, or worse, come postage due to my buyer

. It never occured to me that they WOULDN'T check them! Wow...
Anyway, if you want to be accurate, most PS2 games with bubble mailer and one sheet of paper (I always include a cover letter/invoice) come up to about 6.5 oz - nearly always between 6 and 7, anyway. So I always pay for 7.
Gamecube games are nearly always between 5 and 6 oz - but just the other day I shipped a Super Smash Bros and it came up 6.3 or so, so I had the clerk add a 24 cent stamp to it. It never occured to me to just drop it off and take my chances. Maybe in the future if I'm off by just .1 or .3 oz I'll just let it go :lol:.
Anyway, Xbox games also come up 5-6 oz, and DS and PSP games are always under 5 oz.
So I put 7 for PS2, 6 for GC/Xbox, and 5 for DS/PSP.