garden state plaza is a huge mall at the intersection routes 17 and 4 in paramus. it has everything from high-end to mid-range to lower-end stores, plus a bunch of chain restaurants and a nice movie theater. GSP is the prototypical american megamall with a food court, tons of teenagers and 20-somethings, and a crowded, hectic vibe. it draws shoppers from throughout northern nj and nyc and might just be the most popular mall in the entire nyc region due to its size and proximity to the city.
about 2.5 miles east of GSP is a very upscale mall called the shops at riverside, which is located on route 4 west at hackensack ave in hackensack. unlike GSP, this shopping center is small-to-mid-sized and considerably less crowded/hectic. it also skews toward a affluent middle-aged crowd due to its upscale shops (saks, tiffany, salvatore ferragamo, hermes, burberry, etc) and lack of a food court and movie theater. it also has nicer restaurants than GSP, including a high-end steakhouse (morton's), a popular all-american eatery with a really huge and diverse menu (the cheesecake factory), and a couple of modern american restaurants (houston's, which has good burgers, ribs, and salads, and mccormick & schmick's, which specializes in seafood). all of these places have a busy bar scene, especially the cheesecake factory and houston's. foodwise, i prefer houston's, but in reality all of these places are considerably better than the average suburban chain restaurant.
and there's also a great outlet mall in the region called woodbury common premium outlets, which is located about 32 miles north of GSP in central valley, ny, near the catskill mountains (note: this is upstate ny, NOT new york city). woodbury common outlets is one of the best outlet malls i've ever been to, and certainly tops in the nyc region, as it has almost every high-end store imaginable. just be aware of the fact that it gets insanely crowded on weekends, and as it's an outdoor mall, walking around can be annoying when the weather is lousy.
for mexican cuisine, i would avoid any large chain restaurants (with all due respect for kevin's suggestion), as the food at most mexican chain restaurants isn't that great. the main reasons to go to places like on the border and chevy's are for the huge margaritas, lively bar scene, and large portions of food. that said, i'm assuming you're looking for a place that offers a lot of those same things along with solid, americanized tex-mex food, as opposed to a hardcore authentic taqueria where no english in spoken.
one place that may meet your criteria is mexicali blues cafe in teaneck, which is a live music venue and bar that serves mexican food. i haven't been there in a long time but i remember the food being surprisingly decent, albeit americanized. the reviews i've read on other sites suggests that the food can be hit-or-miss these days depending on what you order, but if you're looking for a good nightlife/live music/bar scene with decent food, this place may fit the bill, although it might be better as a snack place than a full dinner spot:
Mexicali Live - Teaneck, NJ
Mexicali Live | NJ Hottest Live Music Venue
a more traditional restaurant suggestion would be blue moon cafe in englewood, which is about 10 minutes east of paramus. this is a local chain serving americanized mexican cuisine with an emphasis on guacamole, nachos, margaritas, and the like. if you have high standards for authenticity, then this place isn't for you. but if you want a place with a late 20s/30s crowd, good drinks, and sizable portions of tex-mex food, then you'll probably like it. the place has outdoor sidewalk seating and is located in englewood's walkable, attractive, and busy downtown commercial district:
Blue Moon Mexican Cafe - Englewood, NJ
Blue Moon Mexican Cafe
a third choice with a similar vibe and offerings is mama mexico, which is located about 15 minutes east of paramus near the george washington bridge in englewood cliffs. this is another spot with a busy bar scene and americanized mexican food. they have a couple of branches in nyc, but this is their one suburban outpost.
Mama Mexico - Englewood Cliffs, NJ
http://www.mamamexico.com/
if you're looking for more authentic mexican food, check out the following link for suggestions:
Authentic Mexican in northern NJ (Bergen County) - Tristate Region - Chowhound
authentic mexican food has become more widely available in north jersey/nyc in the past 10+ years, but as far as quality goes, it still can't compare with the offerings in california or the american southwest.
as for more bars...well, bergen county is very suburban, so most of the popular bars are going to be located inside busy resturants such as the ones i suggested above. there is a much better bar/nightlife scene in manhattan, of course. if you don't want to cross the hudson river, check out hoboken and downtown jersey city. hoboken has a large frat boy/meathead/20-something element, especially on weekends, but there are an increasing number of lounges and other spots that cater toward a more mature 30-something crowd. downtown jc's bar scene is a little more scattered, but it has a nice mix of loungey places and dives.
i'd also recommend checking out the ironbound district in newark, which is the largest portuguese/brazilian neighborhood in the entire nyc metro area. i'd recommend mampou for an iberian tapas bar with a nice bar scene, pretty decent food, and occasional live jazz:
Mompou - Newark, NJ
Mompou Contact
note that most of the iberian spots in newark are stuffy or are loud tourist traps/food factories. mampou is one of the only places in that area that is kind of young and hip.