Should I play games in order?

I recently got myself a new graphics card in order to expand my choice of games to play. Two I want to try are Mass Effect and Left 4 Dead (spurred somewhat by the threads here, incidentally). However, each has a sequal. Should I play in order, or doesn’t it matter? I know the storyline would be richer if I play ME1 first, but is the same true of L4D? Should I get my skills up to par in 1 before trying L4D2?

Mass Effect? Absolutely. It’s not simply about the storyline either; your save game from ME1 determines portions of ME2.

L4D? I’d recommend it just because the first one was a good game and after playing an improved sequel it’s hard to go back to the previous one. Of course if you really want to jump into L4D2 then you won’t be losing anything.

I played Half Life after completing all commercially available HL2 incarnations.

It’s interesting in a ‘prequel’ kind of way to see the characters you met in one game being introduced in another.

Good to know. L4D2 looks pretty expensive now, though I will get Mass Effect. Thanks!