Hi,
I need a very reliable download manager in Linux like "Flashget" in windows. Because I don't want to lose the parts that has been already downloaded because of power failure or improper shutdown.

The download manager should have following features-

1. Resumable

2. Data protection - After power failure data must be protected and download should resume from the point it stopped due to power failure.

3. Use maximum bandwidth of the connection for downloading.

Now only lack of a reliable download manager kept my one pc using windows. {I guess this would be my final day of using windows anymore...at least the pirated one }

So, please help me to get out of it with satisfaction.

I would just use wget to do all of that. If you are looking for something graphical, I would imagine there are GUI front-ends for wget, but I have never used them.

d4x probably your choice

If I were you, I'll try wget

Kget and gwget work really well for me. They are GUI frontends to wget and support the features you are looking for.