in my opinion it is the Solo Stradivarius by Garritan. This is not the one included in GPO, it is it's own thing. I know Garritan makes "bargain" products, but their solo Violin & Gofriller cello are simply incredible.
You load one instrument - that's it. There are keyswitches that control the different articulations. The other thing that is amazing (and is being copies by HS I think) is how the actual legato playing is. If two notes are connected they are played legato, and the speed of the legato is controlled by how hard you hit the second note (tight all the way to port) - there is also a keyswitch to disable legato for chord playing. The second cool thing is that the mod wheel controls the vibrato volume while aftertouch controls the rate of vibrato.
Anyway, I could go on for weeks about how incredible those two libraries are. I'm not sure if anything will ever beat them.
This one crops up quite regualrly. My favourite for lots of 'out of the box'expression and built in vibrato is the Kirk Hunter Romantic Violin. A very cheap download and superb value for money. The demo on the KH site is probably one of the most realistic I've heard. However, this is for dramatic and romantic use - great for a violin concerto or where the soloist is playing against an orchestra. So it isn't ideal for every situation. KH also has other solo strings that are worth looking at.
The XSample chamber instruments probably work better for more intimate chamber settings. They have a lovely rounded tone and come with templates for Finale and Sibelius.
EastWest Gypsy is supposed to be very good but I have no first hand experience of it. Likewise, you might consider the first chair LASS samples. The solo instruments that come with complete orchestral libraries tend to be less good but I suspect Vienna has some suitable offerings. The ones that come with EastWest SO are very troublesome as they 'move around the stage' - the quality control just isn't good enough for serious use although they served me well to a point.
This may sound odd, but I ended up using both KH and XSample in the same piece. When I needed less vib, I switched from KH to XS and back again. Both sound very good and I doubt the unsuspecting listener could tell. The piece in question is my Romanza at www.soundclick.com/grahamkeitch (first track). This is all KH but I have a much better version that uses XS too. I haven't uploaded this yet as it would reset my chart position (for what that's worth)! My point is that you may need more than one instrument to cover different requirements.
I see Keith has suggested the Garritan product. This too is very good (probably groundbreaking a few years ago) but I think it's discountinued. Keith has done some great stuff with this. It's worth looking out for.
I bought the garritan violin and it was stolen. I liked it but it is not available. I heard that they were coming out with another one. I dont want to buy a whole library to get just the violin. I have been impressed with the demos from KH and gypsy. I would get the garritan violin if I could. I cant believe they discontinued it and didnt replace it yet. If anyone wants to sell the garritan Im interested
i'll put in a 'wanted to buy' notice along with jeff4h, as i'm still kicking myself for not getting the strad when it was still available. i have the cello and imo the control structure (legato, bow/up down, vibrato etc) is the best out there. really fun to play, and easy to get reasonably realistic results.
the other things i forgot to mention about the garritan solo strings are these:
1. it takes up soooo little ram compared to other deeply sample solo libraries.
2. when you use your pitch bend wheel it doesn't sound fake. i don't know how they did it, but they did. for example, if you play a D then bend down to the C, it sounds exactly the same as if you just played a C.
also, don't forget that it is JUST ONE INSTRUMENT. you don't have to load the pizz, the spicatto, marcato, staccato, tremolo, etc. it's all just there.
For realism I much prefer the LASS solo violin to the Garritan.
Yes and most people actually forgot that the full LASS also comes with Bonus solo violin, which was the "proof of concept" instrument, before Andrew recorded the official LASS. It's included there just for fun, but it's recorded in much closer position than the 1st chair violin in LASS and has a really really nice intimate quality.
Also, even though you didn't ask this, I think LASS shines especially in the lower register strings (viola, cello) if you want those as solo, then LASS is particularly good for you. Although the 1st chair violin is well programmed and very musica, I think it's a bit too far away from the mic. Which is of course because it's ment to be a 1st chair violin in orchestra, not just any regular solo violin. But like I said, this is where the Bonus solo violin compensates greatly.
Andrew if you read this, does the Bonus violin come with the LASS first chair package or only the full version?