Hi all

I am a new member to the forum, i am just getting back into biking after being away from it for about 7 years. at the moment i dont have a very big budget for a bike either, but will be saving to invest in my dream bike in the future, i would like to get your opinions on the below listed bikes, and let me know which of the ones i have listed, would be the best choice for my needs and if any of them are better made parts etc. than the others, and what u would upgrade on the one you choose.
i will be using the bike for short rides 3 to 4 times a week, on asphalt, some dirt trails, a few very small hills, 2 to 6 miles rides each outing till i get my endurance built back up. i am also not sure if i should go with a bike that has no speeds or a bike with speeds.
thanks for any input that you may have.

here are the ones i am debating between:

http://www.walmart.com/ip/Schwinn-Al...-Bike/15711179

http://www.walmart.com/ip/26-Women-s...-Bike/13398152

http://www.walmart.com/ip/Schwinn-Si...-Bike/15711175

http://www.walmart.com/ip/NEXT-Avalo...-Bike/14272885

http://www.walmart.com/ip/26-Women-s...-Bike/13398136

or if you recommend a single speed bike, looking at this one:

http://www.walmart.com/ip/26-L-Cranb...green/12509650

thanks again