Thunderbird cannot do the reminders and tasks like Outlook.
I use Thunderbird and love it. It is safer than OL or OE. But for what you use it for you need OL.
TB is great for just email. The only thing I use OL for is to get my email from the company Exchange server. I wish they would make TB compatible with things like that. I really hate using OL or OE.
Firefox on the other hand can be used and will help tremendously with security.
8 Pro 64bit
AMD FX 8350
Asus Sabertooth 990FX R2.0
16GB G.Skill Sniper 1866MHz
OCZ Vertex 4 128GB SSD
HDD's 750GB x2/500GB/250GB
2x XFX 6870 1GB
PC P&C 750W PSU
Cooler Master HAF 932 Red LED
CM Hyper 212 EVO w/2x SickleFlow 120mm Red LED
Logitech X540 5.1 Surround
2X Acer 23" LED - Eyefinity: 3840x1080
"The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
- Albert Einstein