Kawashima Ami, introduced in the 5th episode of Toradora!, has the same given name (first name) as Sailor Mercury's civilian form; not only is the name the same pronunciation, but they share the same kanji (Chinese characters).
川嶋 亜美 (Kawashima Ami)
水野 亜美 (Mizuno Ami)
「川嶋」means "river" + "island," and「水野」means "water" + "field," so both have a water theme and sound refreshing.
「亜美」is harder to translate, since「亜」is never used alone (it can have a meaning of "sub-" but that is not the intended meaning here). 「美」means beautiful, so it is a very well-liked kanji for girls' names and is highly-respected.
逢坂 大河 (Aisaka Taiga), in contrast, does not connote lovely images in the same way.「逢」means "meeting" or "rendezvous" and 「坂」 means "slope" or "hill." 「大河」does have a water image, since it means "large river," but it also has general associations in Japanse culture which do not conjure up the image of refreshing water, such as 「大河ドラマ」(taiga dorama), which are dramatic TV series set in a historical period, and the phrase「大河小説」(taiga shosetsu), meaning a sequence of novels that carry over a theme, a.k.a. roman-fleuve. 「大」is not a terribly common kanji for girls' names since it means "big" or "large" (it does have positive meanings, like in combinations for "great" or "serious"). Although the main Japanese word for "tiger" is 「トラ」(tora),「タイガー」(taigaa) is also possible (especially for names of sports teams such as the 「阪神タイガース」 [Hanshin Taigaasu]), so her nickname may be a play on words.
Mizuno Ami and Sailor Mercury (ranked separately) have consistently placed high in character popularity polls. She beat all other female anime characters for the #1 spot in Animage magazine's May 1993 poll, so she is well-known for being intelligent (with a genius IQ), enduringly popular with male otaku, and generally well-liked. She is not considered tall (among the original five sailor soldiers, Sailor Jupiter is known as being the tall one, but she is later shorter comparatively to some of the outer solar system soldiers and Starlights).