I don't wanna start the new thread for this, cause it concerns only to Lisa fans I think. Especially while the current theme means such reasonings.
The point is in that.

How frequently you need the maintenance of your fans feelings to Lisa?
I mean all: how frequently you think about her; how often recollect her in a daily life, in all this crush and turmoil. Maybe you wear some kind of T-shirt with her bright face? Or maybe you are such lucky beggar, who already have a person anyhow constantly reminding to you itself Her?

As for me I don't have the instant feeling of Lisa somewhere inside myself I always need some "feeding" you know. I mean to see the good pictures with her drawed by a wonderful hands of an artists, to read some fanfiction, to read related to Lisa threads (oh, especially on UFSF) and to see that unical careful attitude of some other people to her. But most of all i need to see the original. The selected and simply fortuitous chosen episodes with Lisa's presence. And of course to do much of framegrabs, purposefully picking out the "special" moments with her.
If i don't receive it, my adoration dies away, til it disappears yet absolutely.
But how it is pleasant to return back to life after almost dead condition and to feel again somewhere inside of you these notes of easy music that heats our hearts so hotly!
* imagines how fondly, slightly...strokes the beautiful disobedient hairs of a wheat colour *

I'm not that much of a Lisa fan that I think about her all day. I do find Lisa to be a very complex and multi faceted character.

On a side note, what are your opinions on Yeardley Smith?

Keeping Lisa's voice consistent isn't really hard for Yeardley, because she sounds like that in real life.

I havent had the same exact voice for 10 years, I doubt anyone has. Exept for Stephen Hawking. Even Jeremy Clarkson's voice has changed a little. But you could look at a Simpsons episode from 1989, and an episode in 2007, they'd sound exactly the same. Ish.
I remember hearing Eric Cartmans voice after a long time and it was noticably different. Hence, I still hold my judgement stubbornly.

Thats true, I guess from that perspective your right. She doesnt have to try to imitate her character as much as the other cast characters, since they have such a wide range of voices to use where as Yeardley has just one character (as far as I know). I havent heard Yeardleys real voice, ever... so I'm just asuming she puts some effort into it. Unlike, for example, Guest Stars who try to sound as normal as posible. Is that correct? 

I loved Yeardley's voice in earlier episodes, she was more childish, less nasal, more sweet all around:
As for her best performance ever, it's not an episode imho, but a song:
"God Bless the Child"!

Ooh, that song is one of my favorites, I listen it from time to time.
Funny, but when I thing about Lisa, I very rarely (read: never) remember about Yeardley... maybe it's my usual carelessness, maybe I'm too attracted to Lisa to care about her voice. But to me, Lisa and Yeardley are generally two different people that for some reason have the same voice... this doesn't make it (voice) any worse of course I love it no matter did it change throughout the past years or not.