Can I keep bitcoins offline? Best wallet? Best forex? bitcom wallet viruses?

[TonyT]

Can I keep bitcoins offline? Best wallet? Best forex?

I read bitcoins can be kept offline but how to buy them, if you don't know if the seller is trustworthy?   

What is the best wallet for online transactions?  For offline I guess you can store the private key anywhere secure, like print it on paper and put it in a safe, or similar encryption scheme on your hard drive.  The trouble is, I read there are 'bitcom wallet viruses' that somehow live online and will (I guess) try and infect your machine if you go to a bitcom site like presumably a online wallet site, and then suck the bitcoins out of your online wallet.  Hence my question about online wallets.  Offline I don't have any problem with (either offline wallets that generate a public key and keep your private key secure--btw, which open source or otherwise offline wallet is the best?), but it raises the question whether you can trade bitcom coins without having an online wallet.  For example, at Mt. Gox bitcoin exchange, do they allow you to "settle" a trade without having an online wallet with bitcoins in their possession?  I doubt it.  So if you convert bitcoins to dollars at Mt. Gox or elsewhere, you need an online wallet maybe, with the virus problem I mentioned above.

BTW if you have a favorite place to buy bitcoins please do post here.  I would imagine most of them have the same prices, as more or less determined by Mt. Gox, but with the rapid daily fluctuations we had recently the highs and lows may vary widely interday.

TonyT

[PenAndPaper]

I don't think there is an answer in the best wallet question. Multibit is nice for starters though.
Also about buying bitcoins it depends from where you are. In Europe Bitstamp is the way to go for example.

[BitcoinBrands]

Multibit and Armory are good. Always transfer your coins onto those from your online wallet as soon as you can.

The only real purpose of an online wallet is to trade for other coins, purchase or sell on an exchange. Otherwise you are leaving your coins open to hacking and theft. It's much more secure to have them on the two softwares above.

[beetcoin]

i use electrum - check it out. it's not very difficult to learn how to use. armory seemed a bit more confusing, but it's probably not that hard either.