When it was still available, TXP-320 was bar none my favorite. I'm just sorry that I didn't get a 220-capable camera until shortly after it was discontinued, but I tried a roll, loved it, and bought up all I could find. I still have some. I've since picked up a few boxes of it in 120, but my only recollection of the most recent stock(I think it was discontinued in 2008?) was in 220. Of course it's still available fresh in sheet film, but that's another perpetual annoyance-I can't shoot the same B&W stock in roll and sheet film(since TX400 isn't made in sheets).
TX-400 in D76 1:1 is close enough for me, but I'd still take the 320 version in a second. I doubt it's ever coming back. though, given that Kodak has gone to great lengths to simplify their product line(at that time there were 6 different Portra stocks and 5 different Ektachrome stocks-that's gone to 3 and 1).
For color, if I can get it, Velvia 100, although anymore any Fuji stock is iffy and of course RVP-100 probably isn't coming back in the US. E100 is decent, and I'll settle for RVP-50 if that's the option, but to me RVP-100 has always been more like RVP than RVP-50 is. Back when I first got into this, I came to really like EPP also, especially as it had such a different look from anything else on the market. It reminded me a lot of Elite Chrome, which I've shot probably hundreds of rolls of in 35mm(and if I'm not mistaken, EPP and Elite Chrome were the same generation so that's probably not coincidental). With that said, everything about C-41 is easier these days, so I've grudgingly added Ektar 1090 and Portra 160/400 into my rotation. In the past month I've shot a few rolls of Gold 200, and even though I never really took to it in 35mm, it seems to have a different feel in MF and I can see myself shooting more of it going forward.