I'm not sure it's the case with things like this, and I haven't encountered it so far ...

But, in some songs or games or manga or whatever, sometimes they use different kanji, or 'special' kanji, or normal kanji with a different-than-normal reading for ... Well, I suppose artistic reasons. (In D.Gray-man, they use '神' and put in furigana イノセンス (ehm if that's spelled correctly~ 'innocence' next to it. While they normally just put イノセンス, I've seen other kanji used for 'イノセンス' as well.))
And I think it's incredibly funny when they put the normal kanji for something, and give an English pronunciation for it in furi. I guess that's to give the meaning for the readers but also have the cool English word?

As for 思　and 想... maybe it's just preference... or because one is more 'special' that they are used at times. (Like English writers sometimes like to use rarer words ... just because?) ...

I have to say though, I haven't come across these examples (聞く and 聴く, 思　and 想) so I'm just guessing. ^_^;

deathspi wrote:

I`ve noticed that too, and it also seems to be the case other kanji such as for 聞く and 聴く.

The difference for this one is that the former is for when you hear something, the latter is for when you really listen to it; use the latter for when you're talking about listening to music for example.

miru does this too

見る - normal miru
観る - see a movie, view flowers
診る - when a doctor examines you (脈を診る)

看る・視る - I haven't seen these enough to be confident. I'm hoping they follow RTK's nuances. They seem to to me anyway.

想う　is more emotional than 思う. You use 思う to say what you think about things/situations, but 想う is used when you're thinking about people.

Consider the example 思い出　vs 想い出. Both mean to remember/be reminded about something. Although it's rare to see 想い出, I recently saw it on the front cover of a photo album.