I don't rewatch anime until 2 or 3 years later.
That's why I downloaded them..to watch them a few years down the road.
But I'm planning to rewatch Higurashi no Naku Koro ni, I'm not even one year finished with it but
I just love it that much.
Some 5-6 years ago, back when i was a total yu-gi-oh! tard i rewatched the seasons one after another. Tho, truth be said, i didn't do it because i wanted to. The TV provider simply didn't dub the new seasons and re-played the first season over and over
The only anime i watched twice, because i wanted it was...
Elfen Lied! I have it on DVD so I can re-watch the entire series whenever I feel like it :3 It just so happens to be one, if not, my favourite series ever. What's attractive about it is that it doesn't have too many episodes and they've condensed all the content into 13 interesting and intriguing episodes. That's all I need in an anime to keep me watching.
Can't rewatch much now, but in my childhood it was Dragon Ball, Pokemon[at least the first series], Digimon, Sailor Moon, anything that was running on RTL2 in the nineties, Record of Lodoss War, NGE, Hellsing, Blue Submarine No. 6, maybe some more on VOX. XD First once trice or more, rest two times, maybe trice, backlog is just to big. I would like to rewatch Terra e with the original movie sometime though...
I'm not a big fan of rewatching anime because it's just so time consuming - and I prefer to use this time to watch anime which are new to me. When something is especially epic and not too long I do rewatch it but there still aren't more than a handfull of series I completely rewatched.
Some months ago I rewatched Death Note and I really enjoyed it. It's fun to see how you look at things differently compared to a few years ago when you watched it for the first time.
Recently rewatched AnoHana which I enjoyed even more than when I watched it for the first time. It was a pleasent surprise and made me cherish the anime even more~
Two anime series that I constantly rewatch are Evangelion and Bebop. The funny thing is that such habit didn't grow out of necessities wanting to be nostalgic, but because sometimes I think that newer Anime sometime is boring or painful to watch. Well, truth to be told, in case of Evangelion, it is an anime which awoke my interest on Anime, so I have to watch it at least once every year.
For Anime movies.. it's going to be a long list if I list them here. I rewatch so many movies because I've nothing to do when I'm waiting/travelling and so on. I also tend to skip the parts where its boring, so you could say that I'm not really rewatching it.
Vampire Hunter D: Bloodlust, it's actually the only anime I own. I am in general not a fan of rewatching media, cause there is so much that I haven't seen so I would rather use the time for that. Occasionally a really good film (anime or otherwise) is worth it for me, but series (TV or anime) are such time investments that once is enough.
dbz, about 8 times all the way through (minus filler)
naruto twice minus filler)
bleach (twice for all but three for the SS arc) (minus filler)
one piece (on second way through now)
most of inuyasha twice
most of yuyu hakusho twice
gundam wing twice