We use Klim gear and feel it's the best stuff out there, bar none.  Not sure what size? Here's Klim's sizing chart http://www.klimusa.com/f/sizes.html 

One thing to note on colors..  Klim calls black "Gray".  If you want black, order "gray".  If you want gray, order "light gray".  Clear as mud?  Let us know if you have any question, that's what we're here for.

Here's what they say: 

The ride started with a nip in the air. Thirty miles later it is sunny and warm. Like a chameleon, the Dakar Pant, with its controlled ventilation chassis, changes to meet the demands of any condition with little adjustment. The Dakar can adapt with the help of 20 inch mesh-lined zippered thigh vents and a mesh-lined rear leg vent. Adaptation does not come at the cost of performance and durability. The Dakar Pant is built with TNP heat and abrasion- resistant leather panels on the inner legs, Cordura® fabric for strength and highly reinforced knees and seat. Be ready to take the lead no matter the condition with the Dakar Pant. 

• Controlled Ventilation Chassis 
• Designed To Be Worn Over The Boot
• 2 Dual Adjustable 20” Thigh Mesh-Lined Vents With Dual Zipper Heads
• Ballistic Panels In High-Wear Areas
• Removable Hip & Knee Pads  
• 840 Denier Cordura® Fabric 
• 1,682 Denier Nylon In Seat & Knees
• Polyester Ribbed Stretch Crotch Gusset & Above Knee & Seat Area To Allow Pant To Move With Rider
• Adjustable Velcro Cuff Closure
• Adjustable Pant Cuff Opening Design Allows Rider To Access & Adjust Knee Brace, Sock And Boot
• Velcro Waist Adjusters
• Auto-Lock & High Durability YKK® Zippers 
• Storm Flap On Front Fly
• Mesh-Lined Rear Leg Vent 
• Two Large Volume Side Leg Velcro Cargo Pockets 
• Wicking Polyester Mesh Lining With Lycra Stretch Panels & Knee Brace Reinforced Cordura® Inner Knee Panels
• Liner Stretch Panels Match Stretch Panels On Shell Of Pant So Liner Moves With Shell Of Pant 
• High-Back Self Adjusting Elastic Yoke To Help Prevent Plumber Crack Dirt Scoop 
• High Quality EMbroidered Graphics 
• Reflective Industrial-Grade 3M™ Piping Accents 
• Improved High-Tenacity Stitching Thread With Double-Stitching & Bar-Tacks
• DWR Coated To Shed Water
• D-Ring