It's probably been asked before, but I haven't found it in my searching.
So what do I do here?

The DVD in question is R2 release of the S. Korean film "The Host". I realised I'd forgot to add it to my collection, so I went to get the UPC from the case and found that on the back of the slipcover it's 5060034579120, but on the back of the keep case it's 5060034579571.

Both UPCs exist in the database (though neither have the slipcover checked at present!!).
Both have the same release date, so it's not like one version was released later with (or without) a slipcover, they were released on the same day. This makes me pretty sure it's not a "mistake" - i.e. it's not as if someone in the factory has accidentally stuck the wrong keep case inside the slipcover.

In other releases they've avoided the UPC difference by doing one of the following:
1) Covering the barcode on either the keep case or the slipcover with a blank sticker or some other method of blanking.
2) Covering the barcode on either the keep case or the slipcover with a sticker that contains the barcode of the other, so the two match.
3) Sometimes when the barcode on the keep case and the slipcover are lined up, a rectangular hole is cut into the slipcover so the barcode from the keep case is visible.

In this case, they've done none of the above, and I have 2 UPCs to choose from.
So, do I add the slipcover one, because the release I have has a slipcover?
Or is it that the keep case is the most important bit, and takes precedent over the slipcover?

And might it be possible that somewhere there could be a release of 5060034579120 that does not have a slipcover, or a release of 5060034579571 that does?

Thanks!

Ok, the 2 links you provided are actually for the 2-disc and single disc releases respectively.

I followed the second link and then clicked on the Zavvi listing for the product (http://www.zavvi.co.uk/-dvd-/780443//p.jsf) - this is definitely the single disc release. It has a UPC noted as 5060034579625, and the back cover image (http://www.zavvi.co.uk/images/780/780443_DV_L_B.JPG) matches the listing. The release date for the single disc version is 4 June 2007.


I followed the first link through to Zavvi - where the 2-disc version is listed with the UPC 5060034579571 (http://www.zavvi.co.uk/-dvd-/755488//p.jsf) - the same as the keep case on the version I own. However, if you look at the associated rear cover image for it (http://www.zavvi.co.uk/images/755/755488_DV_L_B.JPG), the UPC is clearly 5060034579120 - the same as on the slipcover of the one I own. The release date they note is 5 March 2007.

I checked the listing at Tesco Jersey (http://www.tesco.com/entertainment/product.aspx?R=755488&&in_merch=1&in_merch_title=Best_Sellers&in_merch_name=Host,+The+[2+Disc+Version]). On that listing there is a rear cover image (http://img.tesco.com/pi/entertainment/DVD/LB/755488_DV_L_B.jpg) and like Zavvi, it shows the slipcover UPC to be 5060034579120 and has a release date noted as 5 March 2007.

I searched at Amazon by UPC, and 5060034579571 brings up a listing of The Host. That listing (http://www.amazon.co.uk/Host-2-DISC-Kang-Ho-Song/dp/B000KRNMVC/ref=sr_1_1?ie=UTF8&s=dvd&qid=1226671745&sr=8-1) has a release date noted of 5 March 2007.

When I searched at Amazon for UPC 5060034579120 (http://www.amazon.co.uk/STEAMBOY-DIRECTORS-DISC-LIMITED-BOXSET/dp/B000RFGON0/ref=sr_1_1?ie=UTF8&s=dvd&qid=1226673031&sr=8-1), it brings up a different film altogether, Steamboy Director's Cut 2-disc Limited Edition Boxset. However, there are no rear case images of this product to prove the UPC is correct and nowhere else seems to sell it.

A Google search for 5060034579120 brings up very few results - the Amazon one for Steamboy, and a different Zavvi link for The Host (http://www.zavvi.co.uk/dvd-Sci:fi-and-Fantasy-Fantasy-15+to+19.99-The-Host/773791/cccr33.r10.1/p.jsf). This one is listed with a release date of 12 March 2007, but there is no rear case image. However, if you zoom the front case image, it has a different sticker, whcih clearly says "2 disc set" and contains a Virgin logo.

This led me to suspect that 5060034579120 might be the UPC of a Virgin Megastores Exclusive version, which is just the regular release plus a slipcase. This seems viable, as Zavvi took over from Virgin.
However, if the version I own is a Virgin Exclusive, then 1) why do Tesco Jersey have the same rear case image? and 2) you would have to assume that Zavvi have mistakenly applied the rear case image of the Exclusive version to their listing of the regular release, and missed it off the listing for the exclusive edition...

I can't be certain where I bought it from - it could have been Virgin / Zavvi, but it could have been HMV. I don't recall it being an exclusive edition and there's certainly nothing on the case that would suggest it is. I guess I need someone else who has this, but definitely didn't buy from Virgin / Zavvi, to confrim that theirs has a slipcover and non-matching UPCs too...

As the scans for the slip-cover version should be from the slip-cover, so should the UPC imho.
This way the screener(s) can check that the correct scan is used. If scans differ from UPC, I think a decline is in progress... 

I've had a similar case where UPC on the slip cover/outer case differed from the DVD cover.  Those were typically store exclusive cover over standard DVD (T2 Extreme DVD was like this although the metal cover was not an exclusive) .  I would treat those as a boxset with single title and add them both to my database.