By default, email attachments and browser downloads are stored at:

    /sdcard/download

Can also be identified by some File Managers as:

    /HWUserData/download

If the device doesn't have a user-replaceable SD card the location should be:

    /mnt/sdcard/Download

<br/>
<sup>Some apps may have their own default location, or save to appropriated locations based on the file extension.</sup>