I can say now that I've finished watching this, that I wish I had watched it back when I first started it, rather than waiting for so long.
I watched the first episode, expecting this to be another boring, predictable slice of life/romantic comedy, and came away wishing there were more episodes, or that they had been longer. I can usually tell what's going to happen and how the characters are going to respond to a situation, and I was constantly surprised by all the little things that made this anime stand out from most others.
I can't say that I have an enormous repetoir of anime under my belt, and I can't name a production company just by looking at a character, but I know good art when I see it, and this was indeed art. Even the background characters had a little something different from them, and they avoided taking the shortcuts that many anime set in school like to take. Namely, graying out characters that were not relevant to the plot. No crowds that looked like big blobs of gray running around. Some of the backgrounds, while properly animated, were bland and unmoving compared the the rest of the scenes, but nothing that really distracts you. Expressions used were often hilarious and appropriate for the mood. Even though this anime isn't centered on violence, there are multiple scenes with moderate violence, that was pulled off amazingly. Without being gory or hard to watch, it was nevertheless able to draw me in with the camera angles and intensity. I never considered it to be unecessary either, as it was never just pointless.
I watched this in it's native language, so I can only speak for the Japanese dub, but the seiyu did an amazing job here, as far as inflections and emotions go. Everything carried over into the anime and flowed with the characters. The first opening theme, "Pre-Parade" and the first ending theme "Vanilla Salt" were more memorable to me than "Silky Heart" and "Orange", the second opening and ending, respectively. I have them on my mp3 player, and sing them out loud quite often, much to the chagrin of those around me. There is very little noticable music during the anime, the silence filled instead with the sound of a group of people, a train, birds, and other background sounds that I found drew me in and made everything more believable.
The characters behaved as they should, but at times surprised me with their actions. Even characters that seemed secondary or even tertiary, all had little roles to play at times during the anime, without diluting the main cast. There was character growth, although it wasn't truly apparent until the second half of the anime. While I would have liked to see a bit more change come about for some of the characters, this is a strong cast and they're all memorable in their own way. I didn't find any character to be annoying, which is quite a feat. I usually find at least one that just rubs me the wrong way, but did not do so with Toradora. Even a character that I thought was dislikable (Kawashima Ami), surprised me with her level of depth.
This anime was like going to a pristine gathering of water after having waded in muddy puddles for most of your life. I started off worrying that I might not like the water, or that it would be like every other puddle, and came away sad to leave it behind. I splashed around, and took a good swim. Sorry if the analogy is off, but I can say this. Toradora is a wonderful anime that no one who claims to enjoy most anime should go without seeing. Don't be like me and put off watching this great show.