If you want to future proof then buying a dual core is the best option. But given your post and also your requirements, here is my honest advice:
You are not an heavy user (Atleast that is what you said) So for occasional gaming, multimedia and browsing I can suggest good phones. While they may not be dual core, but will last you longer and also you can save money. These phones can handle your requirement with ease and also give you a good user experience. For good gaming experience you can always buy the NGPSP because no dual core phones can match it in terms of games availability and quality.
Also remember that the next ICS (Ice cream sandwich) update in OS is said to be compatible with any decently spec'd phones in the market and do not necessarily require dual core phones. Only games and other 3d intensive apps require dual core or better.
These are the phones I believe to be good for your requirements. Please note that this is just my suggestion:
Galaxy S -
Specs -
Samsung I9000 Galaxy S - Full phone specifications
Price - Rs 19800
*Excellent gaming device which is capable of running any games in the market at present, thanks to its A8 hummingbird 1 ghz processor and Powervr SGX 540 GPU (Best in the market for single core)
*Excellent audio device with Wolfson DAC and Dolby 5.1. Makes listening to music pleasurable. I have various android devices, but I have only one best music player and that this Galaxy S.
*Excellent video player that plays HD videos with ease, thanks again to an excellent hardware.
*Super Amoled screen is a delight for Browsing, watching movies, reading etc with unlimited viewing angles.
*You save 5k
Nexus S -
Specs -
Samsung Google Nexus S I9023 - Full phone specifications
Price - 18990 (Recent drop as seen in Ebay India)
*This might the best future proof phone of any Single core phones in the market, given the priority updates directly from Google. While Nexus Prime is the first model to have ICS out of the box. Nexus S is the first device to have ICS update in Android lineup
*Same Audio chip as Galaxy S, so better listening experience. While it does not have the Dolby 5.1, but still a good music player.
*Same processor and hardware as Galaxy S. So will be an excellent device for gaming.
*Super LCD screen that is also good for browsing, reading and watching movies. While some prefer Super Amoled, some prefer Super LCD. The main difference is saturation is higher on Super Amoled which in turn produces dark colors more darker, while SuperLCD produces accurate light colors.
*You save 6K
Also remember that it has only been a few months since dual core phones have been released in the market, so other than LG you might have to wait a little more to buy Samsung or HTC dual core phones for 25k or less. While there might be deals available online, the street prices are firm with 28 and 29k respectively. Also you can buy dual core phones by importing from US and they start from 18k onwards. But I would recommend against it due to absence of warranty for the amount of money you spend.
Hope this helps.
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