Elennsar: The relevant table is 9-2, same page as carrying capacity, page 162, for reference.
Jaron: I wasn't trying to mean that it doesn't matter, it can definitely make a difference if you've got to sneak into somewhere against alert or hard to avoid sentries or the like, but once again, if you've got to infiltrate something carrying enough crud to put you into medium capacity, you either need to a) have a temp buff thrown on your strength because it sucks pretty hard, b) consolidate the unnecessary crap out to leave with the other people in the party until you get back, or c) utilize the access to dimensional storage.
Since the only skills taking a check penalty are balance, climb, escape artist, hide, jump, move silently, sleight of hand, swim (twice), and tumble, I see only two that really consolidating gear down, or just flat out dropping gear won't immediately solve: Escape Artist (depending on the situational use), and Swim (and that just kind of sucks, but hey whatcha gonna do?). The rest, except in an absolute emergency type situation, could easily have gear left to be recovered after the check is done, or you probably shouldn't have your entire adventuring arsenal with you while doing in the first place. If the gear can't be left (balance over thin bridge over an environmental hazard, for example) and the -3 is really that big a problem for you as a rogue, I guarantee the rest of the party is screwed. A small rogue with crappy Str isn't going to be hosed in those situations anyhow, because even with the -3 I'm fairly certain he'll still have a higher modifier to add to the roll than most of the rest of the party. And once again, in combat, drop the carrying device when it starts that has your extra food and such (the non-combat essentials tend to weigh the most, coincidentally) and you won't have to worry about that +3 dex cap to your Armor. That's what I meant when I said "Out of combat, encumbrance isn't an issue. Ever.". If the work around is easy and doesn't take any time or effort to accomplish, then it's not an issue. Not any more of one that keeping track of durations of spell effects and the like, at least, imo.