I have it on a soundtrack. Unfortunately for me, the liner notes are in Korean.
http://www.themoviebox.net/movies/2005/STUVWXYZ/Sympathy-For-Lady-Vengeance/trailer.php
If you play the trailer, it’s the only violin piece that plays. Is it Vivaldi? Bach? And what’s it called? It’s absolutely gorgeous.
It’s a violin version of the larghetto from Vivaldi’s Cessate, Omai Cessate.
I feel so intelligent 
More crap about this piece: Vivaldi wrote a bunch of cantatas, which are significantly less well-known than his massively-whored Four Seasons, which is unfortunate since they are a lot better (IMHO). This one is about a shepherd with major angst and relationship problems. You can hear a sample of the original, vocal version <a href=“http://www.amazon.com/exec/obidos/tg/detail/-/B0000007AM/qid=1127489089/sr=8-1/ref=pd_bbs_1/103-6972581-5309404?v=glance&s=classical&n=507846”>here</a> (it’s the 5th track). The words for the larghetto are:
Ah, ungrateful Dorilla
wishes me to remain unhappy;
ah, ever more pitilessly
she forces out my tears.
For me there is no remedy,
for me no more hope.
Only death will assuage
my bitter pain and sorrow.
Except this is opera, so everything gets repeated 10 times and it takes him about 5 minutes to sing that. See? More than you ever needed to know! Especially since it’s been adapted for violin and probably chosen because it sounded nice, not because of any meaning to the words (which were in Italian, anyway). But, you know, this is the SDMB :3
Thank you!! I looked up the title you gave me and it is it. 
Do you enjoy this particular piece? And are there any widely-available compilations of his that you can recommend? Other composers too, if you feel like it. It’s not like I can differentiate between them. I know very little about classical music at this point.
Thanks again!
Uh… yeah, I guess I like it quite a lot. I don’t think anyone important has bothered to record Vivaldi’s canatas and I don’t know much about his instrumental pieces because I don’t like them. See, I’m probably not the best person to be asking about this since I didn’t start listening to real classical music until about a month ago; before that I just had a stack of midis. Yeah. Midis. I think Andreas Scholl recorded a few of the cantatas and they look like they might be on that CD I failed to link you to (I must stop trying to use html in forums, I must stop trying to use html in forums…) but I only know of them, and not about them, so don’t quote me.
As for other composers, well, if you want to start listening to classical music there are lots of “classical music for beginners” CDs out there and yeah, a lot of people hate them. But they tend to cover a lot of periods and composers so you can pick out what you like. Or if you give me your email I’ll send you my midi stack (what’s left of it, anyway).
Someone better-educated might be able to tell you something more useful…
Thanks, you’ve been so much help!
So I looked at the liner notes of this soundtrack again and found where “Cessage, Omai Cessate” is mentioned. There’s this technically amazing piece on the soundtrack that I really enjoy, called Schumann’s “Caprice No. 24” in A Minor and this version I have is amazing compared to what I’m finding on iTunes. I almost wonder if this was edited in some way because it is flawless to my newbie ears.
It’s so sad to realize what I’ve been missing out on.