That's what I get for posting at three in the morning before thinking through what I'm saying...
First of all, I haven't had Algebra homework, unless you count Abstract Algebra, in six years. I've probably had as much math as anyone on this board. It's hard not to when, in college, you double-major in computer science and physics, and come one class short of a math major.
I guess I just always separated the concept of convergence from the concept of equality. Whenever I studied infinite series, they were always said to "approach" some value, or "converge" to some value (unless they were divergent, of course); the term "equals" was never used. I guess that's where the ambiguity comes in for me. I always thought that when a series converged to a particular value, then it wasn't quite equal to that value, but was inifinitely close to it (as you said, "a numeric evaluation of an infinite sum"). I thought that it was still possible to insert an infinitely small, yet nonzero term between the two. But, if, as you say, "there is no finite difference between the two," then I'll believe that they are equal. The distinction was never made clear when I studied infinite series, and I never questioned it. For the purposes for which I used infinite series, speaking vaguely about convergence rather than explicitly stating equality was sufficient. I suppose it turns out that they are the same.