OK after watching close to a dozen videos, and reading most of this page:
http://www.apfn.org/old/terri.htm here's my conclusion:
first, i don't trust her husband, although his motives COULD be be sincere, but i still don't trust him. however, the videos and testimonies don't demonstrate that Terri has any (hate to say this, but)
intelligence. the tasks she's been asked to perform in those videos are ones that a 2 year old could perform (following a balloon with her eyes, smiling when people touch her and show her affection). so therefore i don't believe that she's completely there. i mean, if she can move her eyes and understand what's being said, then obviously people would've tried communicating with her (i.e. "Terri, move your eyes left for 'yes', or right for 'no')...
particularly her parents. as was mentioned, i think she's just displaying "childlike wonder"...
Does this constitute her being a "vegetable" though? I doubt it, because as far as i knew a vegetable was someone who wasn't conscious of anything going on, they couldn't live without machines supporting them, and were completely and utterly brain dead.
Should she be killed? The whole "but she understands what's going on!!!" argument is invalid at this point. Will she recover? probably not, it's been 15 years and apparently there hasn't been much in the way of change.
the point is not whether she'll recover or not, or whether she's a living, mentally aware person... it's whether the life she's living is worth living. do you think it is? I sure don't, and i'm sure most would agree. If there's no chance she'll ever be anything but a figure on a bed who can't communicate, who can't live on her own, lives each day like the previous, then i say kill her. not "let her die"........ kill her. make it quick, but put her out of her misery. removing the feeding tube is too painful, but there are other methods of terminating someone that are literally painless, can be done in her sleep.