I must certainly not doing this to procrastinate on writing fic, whatever gave you that idea...<.<

Sources are: Internet Movie Firearms Database and Marvel Movies Wikia. With the guns, I link to the actual model, although the specifications for each are at the top of the page.

Natasha Romanoff/Black Widow

Widow's Bite ("prototype laser weapons that fire from two shaped bracelets")*
Handguns: In IM2, a Walther PPK/S (and she added a H&K USP Compact from a Hammer Industries guard). In Avengers, a pair of Glock 26s.
Taser disks
Flashbangs
Garrote
Dagger

Clint Barton/Hawkeye

Compound Bow (Thor)
Double recurve bow, collapsible (Avengers) (wikia page) + mechanized quiver)
Remington 700PSS/700P** - the sniper rifle he reaches for in Thor
Handgun - Heckler & Koch P30 (Avengers)
Dagger

*According to Natasha's comics wikia page, "Black Widow customarily wears two bracelets equipped to discharge the "widow’s bite, high-frequency electrostatic bolts of up to 30,000 volts, capable of stunning even a superhuman opponent at a range of at least 20 feet, shoot tear gas cartridges and act as a radio transmitter. The bracelets’ various functions are activated by galvanic sensors keyed to Black Widow’s wrist musculature." But I am tilting my head at this and going 'okay, comics, you...do that. ????'
**in my own headcanon, I tend to see him with a military-grade sniper rifle as opposed to police-grade, but he and Natasha seem to use a range of differing weapons depending.