Toch Screen Monitor Hardware & Software

I am the volunteer PC guy for a small museum.

I am wanting to set up an video/slide show display using a Win 7 Pro PC so as to have a interctive touch screen monitor with a menu to enable visitors to select from 3 or 4 videos or slide shows.

The monitor needs to be 21" or larger would be ok if can be done $ reasonably.

Can anyone direct me to sites/links/posts to help with this? (My initial thought was to do with a HTML page)

I see 'optical' & 'capacative' touch screens...

Can anyone help me with recomendations as to which (any other) type to use?

Will I need anything specific as far as a graphics adapter?

Sorry for being such a newbie in this area..

Thanks, R