Ohhai wuts taht ticking? Wut, im getting iradiatd? O wel...
That's how the default radiation felt to me (like a minor annoyance), so I changed it. Now:

-Rads accumulate about 2-3 times faster. You can't just be in water all care free now. This affects wading in water, swimming in water, and drinking water (excluding water in your inventory; only worldspace water is affected)

-At 200 Rads: -2 STR -2 PER -2 END -2 AGI

-Each consecutive sickness level increases these penalties by 2, for a maximum of -8 for STR, PER, END, and AGI.

-At 800 Rads, you will begin to irradiate yourself, and will gain +3 rads per second.

-I also changed Rad-Away so it works over 50 seconds (it will give you the same exact amount of recovery)
NOTE: I did this so having over 800 Rads is BAAAAADDDDDDDD. At 100 Medicine skill, Rad-Away will heal 3 Rads/sec for 50 seconds. Having Fatal Rad Poisoning (800+ Rads) will deal out +3 Rads/sec. Only a doctor or My First Infirmary can save you. Having 100 Medicine will only buy you time. If you're under 100 Medicine, you are screwed. Badly.

-On that note, I would recommend a mod that adds a bit of Rad healing to alcoholic drnks. If you're quick enough, you can save yourself from Fatal Rad Poisoning by chugging some Vodka or something >.> . I personally don't have a mod like that, but it's a suggestion.

Requirements:
Nothing you shouldn't have already... FOMM, Fallout 3... the basics.

Install:
Place the esp. files in your Data folder, and activate them in FOMM

Uninstall:
Uncheck the esp. files in FOMM, and delete the esp.

Notes:
-This isn't meant to be realistic, I made this mod for myself and decided to put it here.