see you have a 351 baseband, so that means your Dell 351 recovery. If you try to to update to Gingerbread without fastboot flashing the 350 recovery, it will spit out a FOTA mismatch error... and I promise that little bit of reading is hours away from everything you need to know because the Gingerbread ROM has MANY bugs... you need to know what to do about wifi and data network errors, SD card read and format errors, just to name a couple.
And flashing is anything you have to do that changes the files on the inner memory... fastboot flashing is a form and then flashing files from recovery is flashing...
I'm not trying to talk down to you or be condescending, I'm trying to keep you from making the huge mistake of getting ahead of yourself and then being stuck with a device NO ONE is going to help you with because you refused to prepare yourself...
The only reason I'm even responding is because you at least took a moment to post your specs... for real info you have to go to either XDA or MoDaCo forums, and if you post there not knowing anything, they won't be nice about it
There is NOT ONE SINGLE PROBLEM you can run into that has not been answered somewhere in the XDA Streak forum, and I mean NOT A SINGLE ONE... so read read and then when you think you have it, start all over