Since both city's are right next door doesn't really matter. Both have their bicycle friendly routes and usually you would ride from one through the other. Just yesterday I rode from Tustin, through Irvine to Back Bay, Newport Beach, through Costa Mesa and back to Tustin (35 miles). What you really need to consider are housing pricing. A 2 bedroom apartment in Irvine starts at around $1800 and a 2 bedroom in Newport around $2200. One reason why I live in Tustin (my 2 bedroom is $1500!).
Irvine has many great bike trails/paths. Newport Beach has PCH and the beauty of looking at the water. Irvine is probably more bike friendly with wide bike lanes, many quiet streets etc., Newport Beach can be congested in parts and generally you share the road with traffic.
PS: Since your job is in Laguna Hills why not consider Aliso Viejo, Laguna Hills or Dana Point. All are bike friendly cities (although alittle on the hilly side). If you enjoy mountain biking there's Aliso Wood/Wood Canyon, Laguna Coast Wildnerness and El Moro to ride in. Great playgrounds! I personally think those 3 cities (which are close to your work) are much more bike friendly then either Irvine or Newport Beach. Housing prices are about the same (well less than Newport Beach which would be the highest).
Where's your new job? I have a good friend that works at Qlogic in LH. He has a beautiful condo in Aliso Viejo.
Last edited by Pamestique; 04-01-07 at 07:50 AM.