1. Opera Mini is my browser on my mobile. Its open 24X7 on my mobile. It supports book marks (you can also sync the bookmarks if you have Opera Account), offline reading of the pages, supports https, supports uploading files and its fast.
2. GMail Mobile App is my email client on my mobile. Its faster than the default client. The newer version allows multiple accounts and also allows hosted accounts. It can open basic file formats like txt, doc and jpg. It lacks attachment feature. It also lacks Gchat functionality.This is my second application that will be open as long has my mobile has juice.
3. MobiGenie is my answering machine. It runs locally and hence I do not have to pay my service provider. You can set up many things like answer by voice and record, reply by sms, block the caller etc. You can record custom welcome message in your own voice. You can export the voice message as mp3 files. Thanks to Asgatech company behind MobiGenie.
4. Qik is my live video production house. It runs on my mobile and sends the live video to the world. You can either see my live on qik/thej or at my *live* site. I have used qik to live stream cycling even and a marathon. In future I might even have scheduled live program ( on the lines of schedule live video interviews/podcatst). You can watch the past videos, you can download them for offline viewing too.
5. MgMaps is my map on phone. It has Yahoo, Yahoo India, MS Live, Ask, Open Street and wikimapia on it. It can work with external/internal GPS. It can even pre download the map images and store it on your memory card for offline usage.   It also has subway maps for major cities and FON locations. Geek stuff: It can also display kml files. I usually use it while traveling.
6. Fring is my voip client. I use it log into my skype account. But you can use it log into any SIP account. It works on both edge and wifi. It also supports Yahoo IM , ICQ, MSN and Gtalk.
7. Putty – s2putty is my on the go command line. Its an open source project on sourceforge. It works all most like putty on your desktop. What more do you want as a developer on the go?
8. DEdit is the best text editor on the go. It is the best full screen editor available for s60 phones. It supports different character encoding like ASCII and Unicode.  It supports really big files (mega byte files). It has search/replace and book marking features. Its my IDE on the go.
9. Twitxme or Twitxr is my image/picture uploader. I use it to upload the picture on the go. I have also configured it to upload the same pics to flickr and facebook. It also tweets to my twitter/thej account. It works pretty well.
10. Autolock is also recent addition to my list of software. For some strange reason e61i does not have auto locking feature for keypad. So i had to install this program. It works pretty well but I want PIN support.

Other India Specific Apps

1. ICICI Bank iMobile : Its an awesome banking application. You can do everything that you can do with the regular browser (including money transfer). I must say I more happy customer of ICICI Bank after I got this appliation.
2. IRCTCMobile : Yet another awesome application to have on mobile if you are on the go. You can check the schedule, book the trains and watch booking history. What more you want?

Apps that I have installed but do not use that often

1. WordMobi is wordpress blog client. It can blog to any wordpress installation. You blog/edit posts. Using the client you can even approve/reject comments. It also has an option for photo blogging. You should install Python before installing wordmobi.
2. YouTube Mobile is the recent addition. I use it for uploading than watching.
3. Screenshot is screenshot taker on the go.  I usually use it to take the screen shot of apps running on mobile. It helps when you want to blog about the app.
4. Google Mobile Maps is google maps on the go. Its faster than MgMaps but does not have features.
5. Twibble is mobile twitter client. It has lot more features compared to default mobile site.  It supports twitpic for photo uploading.  I am not using this now.
6. Kyte used to my live video production house before qik. I guess qik does better deferred live ( when bandwith is low for example you are on edge) thank kyte. But kyte has better embdding functionality.
7. UpCode is my QRCode reader.

These are software I have installed but not used yet

1. TringMe Mobile. I have started using tringme. I have not tried trigme mobile yet.
2. Gizmo5 voip client. It also supports other IM protocols.
3. EQO is a voip cum multi protocol IM client.
4. Talkonaut voip cum multi protocol IM client.
5. Booku is a powerful mobile book reader. I am yet to start reading on mobile.
6. Xumii social network for mobile users.

I am yet to install a dictionary,  Mobile Python Editor and an html editor.

I am still looking for

1. Good jabber client. I need a jabber client where I am assured of my password safety. I dont like the services where your password is stored on a server. I want a proper jabber client which stores the password locally or I will wait for Google to integrate chat into mobile app. I am ready to pay if the client is good.
2. Audio recording software. I want a software which I can use to record calls and as well as to record some podcasts or notes. I want the recorder to produce mp3 file. The default note taker is limited by 30 seconds.
3. Need a podcast software which can download podcasts automatically and has the capability of playing them too.
4. FTP client for s60. Its such a big requirement for the developer on the go. Better if can access Amazon s3.
5. Never tried searching but can any of you suggest me good online radio software.
6. Need a paypal client for mobile.
7. Good multi-lingual dictionary

What else do you think I should run on my e61i ? Please suggest if its interesting app.