BTW Metallica is no longer considered heavy metal imo, after hearing the travesty they released a few months ago.
Lulu doesn't exist as far as I'm concerned...
To the OP - there are various different templates for metal videos:
- the live video
Clips of the band performing live, usually in a small club where the crowd is going mental (to imply how passionate fans are about their music, and to show that someone gives a shit), but sometimes at a massive show (to imply they are a massive arena-sized band, and also just because fields full of people getting down is badass cool).
Classic ways to achieve this range from actually filming performances, using fan footage from various shows spliced together, or putting on a specific show to be filmed, sometimes by invite to the fan club to be the audience (which guarantees a good reaction).
Example: Metallica,
Wherever I May Roam
- the performance video
The band performs their song in a setting other than live on stage - a favourite low-budget option is the middle of a forest or in the recording studio. There's a POV difference too, because in a performance video the band is typically performing to the audience behind the camera, instead of an audience in front of them.
Example: Lamb Of God,
Ruin
- the narrative video
A separate story, like a short film. Often features members of the band, and may be thematically linked to the song.
Example: Killswitch Engage,
Save Me
- the lyrics video
A newer phenomenon, where the lyrics are animated to appear in time with the vocals. Helps with understanding the words, and cheap, but not the most interesting thing to do.
Example: As I Lay Dying,
Cauterize
- the random cool stuff video
Just random cool images that aren't predominantly of the band playing or any story.
Example: Deftones,
My Own Summer
Often videos will splice together different styles into a single whole - narrative segments alternated with performance segments is a classic (example: Slipknot,
Left Behind). I personally prefer this, as you get a bit of cool band imagery, and something extra so you don't get bored. What makes the example I cited work particularly for me is the link between the narrative and the performance - the settings complement and give context to each other.
Different approaches suit different genres - for instance, a "home video" style dark forest performance works well for black metal, but wouldn't lend itself to arena rock (although Paramore's
Decode doesn't come off too badly). What particular kind of heavy metal do the band play? Can you post some links where we can listen to help work it out?