Hmmm, if you want pure lumens, I'd say get an L6 if you can find one, or an L4 (both by Surefire). Since Surefires are backordered in many places, and if you want a light that you can carry with you on a daily basis instead of being left at home like the L6 or even the L4, I'd spring for an Arc4+. Not a wopper like Surefire but is most likely brighter than your friend's 7 LED light. Also has a lot of features that you can read about in the Arc forum. Personally, I'd go with the Arc since it will get a lot more use though it would seem "not as cool or sexy" to others as the Surefire lights. It's more bang for the buck IMO. Once you become a true flashaholic, you can start adding some of the sexier Surefires to your collection. I own lights from both companies (both make some of the best engineered lights BTW) but the Arc is the one that gets put into my pants pocket everyday.
CM