Angsty, teen romance suggestions!

[Willen]

Red = unlicensed in the US.

Suzuka. As I watched this series, I found it got more and more cliche. I still recommend a watch, but good luck finding it. It is supposedly going to be licensed, so a US domestic release is hopefully not too far off.

REC. A short but sweet and somewhat angsty romantic series.

Wolf's Rain. Angst. Sadness. Gah.

Chrono Crusade. It starts out all fun and action...

Ai Yori Aoshi. A bit on the fanservice-y side, this quasi-harem anime has it's dramatic sides.

I generally prefer the older stuff like Oh! My Goddess (OVA) and the Ah! My Goddess movie.

For lighter (but longer) fare:

Kimagure Orange Road TV (it's mostly comedy, although there are a few episodes that really stand out emotionally). Try the OVAs and the first movie before you commit to a 48 episode series. It's out of print now, so renting or checking RightStuf may be your best bet.

Maison Ikkoku. It's long at 96 episodes (plus a few specials and movie), but while being mostly comedy, has a strong romantic theme running thoughout (although the characters aren't in their teens). One of the few Rumiko Takahashi series that doesn't overstay its welcome (*cough* Inuyasha *cough*).

And you can't go wrong with shoujo anime:

Fushigi Yuugi and its sequels run the gamut of emotions.

I also recommend The Vision of Escaflowne.

[Shazzy]

Love Hina.

[Alayla]

...they asked for Angsty series.

I agree with the ones above, and give my special remarks to:
AIR
Kanon (both series)
Shuffle!
Kimi Ga Nozomu Eien
Ai Yori Aoshi

[DTJB]

Marmalade Boy. Angst, teens, romance, and sappy as heck!