after doing an extensive research and survey i decided to go for (atleast as of tonight ) garmin c320. reasons... 1. cheaper in the c3xx series for north america 2. maps can be downloaded as required (since thats not a problem for me like some people do and go for 330or 340 which have built in maps) 3. reading from sd memory card and not from a hard drive like in 330. so less power consumption and less chances of crashing... 4. no mp3 player needed for me in this... 5. customised POI's 6. detour calculations... 7. updated maps and software available for free..(but waiting time for the former--they send dvd by snail mail...no iso image to download.)
i prefer this over SP i3,i5 series
1. touch screen 2. bigger screen 3. dont wanna use aa batteries...
well i am not going for other brands coz,
1. survey shows garmin is 'better' in getting signals 2. cost per options.. 3. ergonomic design 4. looks. 5. sweet female british voice 6. i can name it gamina (think of tomtomina?)
) garmin c320. 
(think of tomtomina?)