deinterlace or leave interlaced

[gavo]

If i have a video that being projecting with a projecter through a laptop should I leave it interlaced or deinterlace it or leave it interlaced and get a windvd or core to deinterlace it on the fly.

[rigel]

interlaced video is only for TV.
everywhere else it will look terrible.
whether you deinterlace it beforehand or on-the-fly should not have any impact on quality (if the deinterlace method is the same).
I would suggest that you just test it (because quality is subjective, and also depends on the type of source material).